| 1 |
Two Sum |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 2 |
Add Two Numbers |
LinkedList |
O(n) |
O(1) |
Medium |
|
|
| 3 |
Longest Substring Without Repeating Characters |
Hash Table; Two Pointer |
O(n) |
O(1) |
Medium |
Y |
|
| 4 |
Median of Two Sorted Arrays |
Divide and Conquer |
O(log(m + n)) |
O(1) |
Hard |
Y |
special to [] |
| 5 |
Longest Palindromic Substring |
String |
O(n^2) |
O(1) |
Medium |
|
|
| 6 |
ZigZag Conversion |
String |
O(n) |
O(1) |
Medium |
|
pattern |
| 7 |
Reverse Integer |
Math |
O(n) |
O(1) |
Easy |
|
use long for Overflow |
| 8 |
String to Integer (atoi) |
String |
O(n) |
O(1) |
Medium |
|
long long |
| 9 |
Palindrome Number |
Math | Math |
O(x) (O(1)) |
O(1) |
Easy |
|
compare half, overflow |
| 10 |
Regular Expression Matching |
Recursion | DP |
O(e?) |
O(1) |
Hard |
Y |
DP |
| 11 |
Container With Most Water |
Two Pointers |
O(n) |
O(1) |
Medium |
Y |
|
| 12 |
Integer to Roman |
Solution |
O(n) |
O(1) |
Medium |
|
|
| 13 |
Roman to Integer |
Solution |
O(n) |
O(1) |
Easy |
|
|
| 14 |
Longest Common Prefix |
String |
O(n*k) |
O(1) |
Easy |
|
|
| 15 |
3Sum |
Two Pointers |
O(n^2) |
O(1) |
Medium |
Y |
use set; or skip duplicates |
| 16 |
3Sum Closest |
Two Pointers |
O(n^2) |
O(1) |
Medium |
|
|
| 17 |
Letter Combinations of a Phone Number |
BFS | DFS |
O(4^n) |
O(n) |
Medium |
Y |
|
| 18 |
4Sum |
Two Pointers |
O(n^3) |
O(1) |
Medium |
|
use set; or skip duplicates |
| 19 |
Remove Nth Node From End of List |
Two Pointers |
O(n) |
O(1) |
Medium |
Y |
delete head, tail cases |
| 20 |
Valid Parentheses |
Stack |
O(n) |
O(n) |
Easy |
|
|
| 21 |
Merge Two Sorted Lists |
LinkedList |
O(n) |
O(1) |
Easy |
|
|
| 22 |
Generate Parentheses |
DFS |
? |
O(1) |
Medium |
Y |
|
| 23 |
Merge k Sorted Lists |
Heap |
O(n*k) |
O(k) |
Hard |
Y |
|
| 24 |
Swap Nodes in Pairs |
LinkedList | Recursion |
O(n) |
O(1) |
Medium |
|
|
| 25 |
Reverse Nodes in k-Group |
Recursion |
O(n) |
O(1) |
Hard |
|
|
| 26 |
Remove Duplicates from Sorted Array |
Two Pointer |
O(n) |
O(1) |
Easy |
|
|
| 27 |
Remove Element |
Two Pointer |
O(n) |
O(1) |
Easy |
|
rare |
| 28 |
Implement strStr() |
Two Pointer |
O(n*k) |
O(1) |
Easy |
|
check KMP? |
| 29 |
Divide Two Integers |
Bit Manipulation |
O(logn) |
O(1) |
Medium |
Y |
|
| 30 |
Substring with Concatenation of All Words |
Hash Table |
O(n) |
O(n) |
Hard |
|
|
| 31 |
Next Permutation |
Binary Search |
O(n) |
O(1) |
Medium |
Y |
Binary Search |
| 32 |
Longest Valid Parentheses |
Stack |
O(n) |
O(n) |
Hard |
|
|
| 33 |
Search in Rotated Sorted Array |
Binary Search |
O(logn) |
O(1) |
Medium |
Y |
<= |
| 34 |
Search for a Range |
Binary Search |
O(logn) |
O(1) |
Medium |
|
|
| 35 |
Search Insert Position |
Binary Search |
O(logn) |
O(1) |
Easy |
|
|
| 36 |
Valid Sudoku |
Hash Table |
O(9^2) |
O(1) |
Medium |
|
|
| 37 |
Sudoku Solver |
BackTracking |
O(O((9!)^9)) |
O(1) |
Hard |
|
|
| 38 |
Count and Say |
Solution |
O(n) |
O(1) |
Easy |
|
|
| 39 |
Combination Sum |
DFS |
O(2^n) |
O(1) |
Medium |
|
|
| 40 |
Combination Sum II |
DFS |
O(2^n) |
O(1) |
Medium |
Y |
prev |
| 41 |
First Missing Positive |
Array |
O(n) |
O(1) |
Hard |
Y |
|
| 42 |
Trapping Rain Water |
Two Pointers |
O(n) |
O(1) |
Hard |
|
|
| 43 |
Multiply Strings |
String |
O(m*n) |
O(1) |
Medium |
Y |
|
| 44 |
Wildcard Matching |
Greedy |
O(n) |
O(1) |
Hard |
Y |
|
| 45 |
Jump Game II |
Two Pointer |
O(n) |
O(1) |
Hard |
Y |
|
| 46 |
Permutations |
DFS |
O(n*n!) |
O(n) |
Medium |
|
|
| 47 |
Permutations II |
DFS |Hash Table |
O(n*n!) |
O(n) |
Medium |
Y |
|
| 48 |
Rotate Image |
In Place |
O(n^2) |
O(1) |
Medium |
|
|
| 49 |
Group Anagrams |
Hash Table |
O(m*n) |
O(1) |
Medium |
|
|
| 50 |
Pow(x, n) |
Divide and Conquer |
O(logn) |
O(1) |
Medium |
Y |
|
| 51 |
N-Queens |
BackTracking |
O(exp) |
O(n) |
Hard |
Y |
|
| 52 |
N-Queens II |
Back Tracking |
O(exp) |
O(n) |
Hard |
|
|
| 53 |
Maximum Subarray |
DP | Greedy |
O(n) |
O(1) |
Easy |
Y |
|
| 54 |
Spiral Matrix |
In Place |
O(n^2) |
O(1) |
Medium |
|
|
| 55 |
Jump Game |
Greedy |
O(n) |
O(1) |
Medium |
|
|
| 56 |
Merge Intervals |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 57 |
Insert Interval |
Array |
O(n) |
O(1) |
Hard |
Y |
|
| 58 |
Length of Last Word |
String |
O(n) |
O(1) |
Easy |
|
|
| 59 |
Spiral Matrix II |
In Place |
O(n^2) |
O(1) |
Medium |
|
|
| 60 |
Permutation Sequence |
Recursive | Iterative |
O(n) |
O(1) |
Medium |
Y |
|
| 61 |
Rotate List |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 62 |
Unique Paths |
DP |
O(m*n) |
O(m*n) |
Medium |
|
can make space O(n) |
| 63 |
Unique Paths II |
DP |
O(m*n) |
O(m*n) |
Medium |
|
|
| 64 |
Minimum Path Sum |
DP |
O(m*n) |
O(m*n) |
Medium |
|
|
| 65 |
Valid Number |
String |
O(n) |
O(1) |
Hard |
Y |
|
| 66 |
Plus One |
Math |
O(n) |
O(1) |
Easy |
|
|
| 67 |
Add Binary |
Math |
O(n) |
O(1) |
Easy |
|
|
| 68 |
Text Justification |
String |
O(n) |
O(1) |
Hard |
Y |
|
| 69 |
Sqrt(x) |
Binary Search |
O(logn) |
O(1) |
Easy |
Y |
|
| 70 |
Climbing Stairs |
DP |
O(n) |
O(n); O(1) |
Easy |
|
Fib |
| 71 |
Simplify Path |
Stack |
O(n) |
O(n) |
Medium |
|
Stringstream |
| 72 |
Edit Distance |
DP |
O(n) |
O(1) |
Hard |
Y |
|
| 73 |
Set Matrix Zeroes |
Math |
O(n^2) |
O(1) |
Medium |
|
|
| 74 |
Search a 2D Matrix |
Binary Search |
O(logn) |
O(1) |
Medium |
|
|
| 75 |
Sort Colors |
Two Pointers |
O(n) |
O(1) |
Medium |
Y |
|
| 76 |
Minimum Window Substring |
Two Pointers |
O(n) |
O(1) |
Hard |
Y |
|
| 77 |
Combinations |
Back Tracking |
O(n!) |
O(n) |
Medium |
|
|
| 78 |
Subsets |
Back Tracking |
O(2^n) |
O(1) |
Medium |
|
|
| 79 |
Word Search |
DFS |
O(m*n) |
O(1) |
Medium |
Y |
|
| 80 |
Remove Duplicates from Sorted Array II |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 81 |
Search in Rotated Sorted Array II |
Binary Search |
O(logn) |
O(1) |
Medium |
Y |
worst case O(n) |
| 82 |
Remove Duplicates from Sorted List II |
LinkedList |
O(n) |
O(1) |
Medium |
Y |
|
| 83 |
Remove Duplicates from Sorted List |
LinkedList |
O(n) |
O(1) |
Easy |
|
|
| 84 |
Largest Rectangle in Histogram |
Stack |
O(n) |
O(n) |
Hard |
Y |
|
| 85 |
Maximal Rectangle |
Stack |
O(m*n) |
O(n) |
Hard |
|
|
| 86 |
Partition List |
LinkedList |
O(n) |
O(1) |
Medium |
|
|
| 87 |
Scramble String |
Hash Table, DFS |
O(exp) |
O(m*n) |
Hard |
Y |
|
| 88 |
Merge Sorted Array |
Two Pointers |
O(n) |
O(1) |
Easy |
|
|
| 89 |
Gray Code |
Math |
O(n) |
O(1) |
Medium |
|
|
| 90 |
Subsets II |
DFS1 | DFS2 |
O(2^n) |
O(1) |
Medium |
Y |
sort first |
| 91 |
Decode Ways |
DP |
O(n) |
O(n) |
Medium |
Y |
reduce space |
| 92 |
Reverse Linked List II |
LinkedList |
O(n) |
O(1) |
Medium |
|
|
| 93 |
Restore IP Addresses |
DFS |
O(2^n) |
O(1) |
Medium |
|
|
| 94 |
Binary Tree Inorder Traversal |
Stack |
O(n) |
O(n) |
Medium |
Y |
|
| 95 |
Unique Binary Search Trees II |
DFS |
O(2^n) |
O(n) |
Medium |
Y |
|
| 96 |
Unique Binary Search Trees |
DP | Recursion |
O(n) |
O(n) |
Medium |
Y |
|
| 97 |
Interleaving String |
DP |
O(n^2) |
O(n^2) |
Hard |
|
|
| 98 |
Validate Binary Search Tree |
Inorder | Recursion |
O(n) |
O(1) |
Medium |
Y |
|
| 99 |
Recover Binary Search Tree |
Recursion |
O(n) |
O(1) |
Hard |
|
|
| 100 |
Same Tree |
Recursion |
O(n) |
O(1) |
Easy |
|
|
| 101 |
Symmetric Tree |
Recusion |
O(n) |
O(1) |
Easy |
|
|
| 102 |
Binary Tree Level Order Traversal |
BFS | DFS |
O(n) |
O(n) |
Medium |
Y |
|
| 103 |
Binary Tree Zigzag Level Order Traversal |
Stacks |
O(n) |
O(n) |
Medium |
|
|
| 104 |
Maximum Depth of Binary Tree |
Recursion |
O(n) |
O(1) |
Easy |
|
|
| 105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Recursion |
O(n) |
O(1) |
Medium |
|
|
| 106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Recusion |
O(n) |
O(n) |
Medium |
|
|
| 107 |
Binary Tree Level Order Traversal II |
BFS | DFS |
O(n) |
O(n) |
Easy |
Y |
|
| 108 |
Convert Sorted Array to Binary Search Tree |
Divide and Conquer |
O(logn) |
O(1) |
Easy |
|
|
| 109 |
Convert Sorted List to Binary Search Tree |
Divide and Conquer |
O(logn) |
O(1) |
Medium |
Y |
|
| 110 |
Balanced Binary Tree |
Recursion |
O(n) |
O(h) |
Easy |
|
|
| 111 |
Minimum Depth of Binary Tree |
Recusion |
O(n) |
O(1) |
Easy |
|
null? |
| 112 |
Path Sum |
Recusion |
O(n) |
O(1) |
Easy |
Y |
|
| 113 |
Path Sum II |
Recusion |
O(n) |
O(1) |
Medium |
|
|
| 114 |
Flatten Binary Tree to Linked List |
Recusion |
O(n) |
O(1) |
Medium |
Y |
|
| 115 |
Distinct Subsequences |
DP |
O(m*n) |
O(m*n) |
Hard |
Y |
|
| 116 |
Populating Next Right Pointers in Each Node |
Recusion |
O(n) |
O(1) |
Medium |
|
|
| 117 |
Populating Next Right Pointers in Each Node II |
Recusion |
O(n) |
O(1) |
Medium |
Y |
|
| 118 |
Pascal's Triangle |
Math |
O(n^2) |
O(1) |
Easy |
|
|
| 119 |
Pascal's Triangle II |
Math |
O(n^2) |
O(1) |
Easy |
Y |
|
| 120 |
Triangle |
DP |
O(n) |
O(n) |
Medium |
Y |
|
| 121 |
Best Time to Buy and Sell Stock |
Math |
O(n) |
O(1) |
Easy |
|
|
| 122 |
Best Time to Buy and Sell Stock II |
Greedy |
O(n) |
O(1) |
Easy |
|
|
| 123 |
Best Time to Buy and Sell Stock III |
DP | DP |
O(n) |
O(n) |
Hard |
Y |
|
| 124 |
Binary Tree Maximum Path Sum |
Recusion |
O(n) |
O(n) |
Hard |
Y |
|
| 125 |
Valid Palindrome |
String |
O(n) |
O(1) |
Easy |
|
|
| 126 |
Word Ladder II |
BFS |
O(exp) |
O(n) |
Hard |
Y |
|
| 127 |
Word Ladder |
BFS |
O(n) |
O(n) |
Medium |
Y |
|
| 128 |
Longest Consecutive Sequence |
Hash Table |
O(n) |
O(n) |
Hard |
Y |
|
| 129 |
Sum Root to Leaf Numbers |
DFS |
O(n) |
O(n) |
Medium |
|
|
| 130 |
Surrounded Regions |
DFS |
O(m*n) |
O(1) |
Medium |
Y |
|
| 131 |
Palindrome Partitioning |
DFS |
O(n^2) |
O(n) |
Medium |
|
|
| 132 |
Palindrome Partitioning II |
DP |
O(n^2) |
O(n^2) |
|
|
|
| 133 |
Clone Graph |
BFS, Hash Table |
O(n) |
O(n) |
Medium |
Y |
|
| 134 |
Gas Station |
Greedy |
O(n) |
O(n) |
Hard |
|
|
| 135 |
Candy |
Greedy |
O(n) |
O(n) |
Hard |
|
|
| 136 |
Single Number |
Bit Manipulation |
O(n) |
O(1) |
Easy |
|
|
| 137 |
Single Number II |
Bit Manipulation |
O(n) |
O(1) |
Medium |
|
|
| 138 |
Copy List with Random Pointer |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 139 |
Word Break |
DP |
O(n) |
O(n) |
Medium |
Y |
|
| 140 |
Word Break II |
DP |
O(2^n) |
O(n) |
Hard |
Y |
|
| 141 |
Linked List Cycle |
Two Pointers |
O(n) |
O(1) |
Easy |
|
|
| 142 |
Linked List Cycle II |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 143 |
Reorder List |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 144 |
Binary Tree Preorder Traversal |
Stack |
O(n) |
O(n) |
Medium |
|
|
| 145 |
Binary Tree Postorder Traversal |
Stack |
O(n) |
O(n) |
Hard |
Y |
|
| 146 |
LRU Cache |
List, Hash Table |
O(1) |
O(n) |
Hard |
Y |
|
| 147 |
Insertion Sort List |
Sort |
O(n^2) |
O(1) |
Medium |
|
|
| 148 |
Sort List |
Merge Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 149 |
Max Points on a Line |
Hash Table |
O(n^2) |
O(n) |
Hard |
Y |
gcd |
| 150 |
Evaluate Reverse Polish Notation |
Stack |
O(n) |
O(n) |
Medium |
|
|
| 151 |
Reverse Words in a String |
String |
O(n) |
O(n) |
Medium |
|
|
| 152 |
Maximum Product Subarray |
DP |
O(n) |
O(1) |
Medium |
Y |
|
| 153 |
Find Minimum in Rotated Sorted Array |
Binary Search |
O(logn) |
O(1) |
Medium |
Y |
|
| 154 |
Find Minimum in Rotated Sorted Array II |
Binary Search |
O(n) |
O(1) |
Hard |
Y |
|
| 155 |
Min Stack |
Stack |
O(n) |
O(1) |
Easy |
|
|
| 156 |
Binary Tree Upside Down |
Iterative | Recursive |
O(n) |
O(1) |
Medium |
|
|
| 157 |
Read N Characters Given Read4 |
String |
O(n) |
O(1) |
Easy |
|
|
| 158 |
Read N Characters Given Read4 II - Call multiple times |
String |
O(n) |
O(1) |
Hard |
Y |
|
| 159 |
Longest Substring with At Most Two Distinct Characters |
Hash Table |
O(n) |
O(1) |
Hard |
|
|
| 160 |
Intersection of Two Linked Lists |
Two Pointers |
O(n) |
O(1) |
Easy |
|
|
| 161 |
One Edit Distance |
String |
O(n) |
O(1) |
Medium |
|
|
| 162 |
Find Peak Element |
Binary Search |
O(logn) |
O(1) |
Medium |
Y |
|
| 163 |
Missing Ranges |
Array |
O(n) |
O(1) |
Medium |
|
|
| 164 |
Maximum Gap |
Bucket Sort |
O(n) |
O(n) |
Hard |
Y |
|
| 165 |
Compare Version Numbers |
String |
O(n) |
O(1) |
Medium |
|
replace |
| 166 |
Fraction to Recurring Decimal |
Hash Table |
O(n) |
O(1) |
Medium |
|
|
| 167 |
Two Sum II - Input array is sorted |
Two Pointer |
O(n) |
O(1) |
Easy |
|
|
| 168 |
Excel Sheet Column Title |
Math |
O(logn) |
O(1) |
Easy |
|
|
| 169 |
Majority Element |
Math |
O(n) |
O(1) |
Easy |
|
|
| 170 |
Two Sum III - Data structure design |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 171 |
Excel Sheet Column Number |
Math |
O(n) |
O(1) |
Easy |
|
|
| 172 |
Factorial Trailing Zeroes |
Math |
O(logn) |
O(1) |
Easy |
|
|
| 173 |
Binary Search Tree Iterator |
Stack |
O(n) |
O(n) |
Medium |
Y |
|
| 174 |
Dungeon Game |
DP |
O(m*n) |
O(m*n) |
Hard |
|
|
| 179 |
Largest Number |
Sort |
O(nlogn) |
O(1) |
Medium |
|
comparator |
| 186 |
Reverse Words in a String II |
String |
O(n) |
O(1) |
Medium |
|
|
| 187 |
Repeated DNA Sequences |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 188 |
Best Time to Buy and Sell Stock IV |
DP |
O(n) |
O(n) |
Hard |
Y |
|
| 189 |
Rotate Array |
String |
O(n) |
O(1) |
Easy |
|
|
| 190 |
Reverse Bits |
Bit Manipulation |
O(1) |
O(1) |
Easy |
|
|
| 191 |
Number of 1 Bits |
Bit Manipulation |
O(1) |
O(1) |
Easy |
|
|
| 198 |
House Robber |
DP |
O(n) |
O(n) |
Easy |
|
|
| 199 |
Binary Tree Right Side View |
Recursion |
O(n) |
O(1) |
Medium |
|
|
| 200 |
Number of Islands |
DFS | BFS |
O(n) |
O(n) |
Medium |
Y |
visited |
| 201 |
Bitwise AND of Numbers Range |
Bit Manipulation |
O(1) |
O(1) |
Medium |
|
|
| 202 |
Happy Number |
Math |
O(n) |
O(1) |
Easy |
|
|
| 203 |
Remove Linked List Elements |
Linked List |
O(n) |
O(1) |
Easy |
|
|
| 204 |
Count Primes |
Math |
O(n) |
O(n) |
Easy |
Y |
|
| 205 |
Isomorphic Strings |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 206 |
Reverse Linked List |
Linked List |
O(n) |
O(1) |
Easy |
|
|
| 207 |
Course Schedule |
Topological Sort |
O(n) |
O(n) |
Medium |
|
|
| 208 |
Implement Trie (Prefix Tree) |
Trie |
O(1) |
O(1) |
Medium |
Y |
|
| 209 |
Minimum Size Subarray Sum |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 210 |
Course Schedule II |
Topological Sort |
O(n) |
O(n) |
Medium |
Y |
|
| 211 |
Add and Search Word - Data structure design |
Trie + BT |
O(n) |
O(n) |
Medium |
|
|
| 212 |
Word Search II |
DFS |
O(n!) |
O(1) |
Hard |
Y |
! |
| 213 |
House Robber II |
DP |
O(n) |
O(n) |
Medium |
|
|
| 214 |
Shortest Palindrome |
String |
O(n) |
O(1) |
Hard |
|
|
| 215 |
Kth Largest Element in an Array |
Quick Select |
O(n) |
O(1) |
Medium |
Y |
|
| 216 |
Combination Sum III |
Recursion |
O(n!) |
O(n) |
Medium |
Y |
|
| 217 |
Contains Duplicate |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 218 |
The Skyline Problem |
Heap |
O(nlogn) |
O(n) |
Hard |
Y |
|
| 219 |
Contains Duplicate II |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 220 |
Contains Duplicate III |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 221 |
Maximal Square |
DP |
O(n^2) |
O(n^2) |
Medium |
|
|
| 222 |
Count Complete Tree Nodes |
Recursion |
O(n) |
O(1) |
Medium |
Y |
|
| 223 |
Rectangle Area |
Math |
O(1) |
O(1) |
Medium |
|
|
| 224 |
Basic Calculator |
Stack |
O(n) |
O(1) |
Hard |
Y |
|
| 225 |
Implement Stack using Queues |
Queue |
O(n) |
O(n) |
Easy |
|
|
| 226 |
Invert Binary Tree |
Tree |
O(n) |
O(1) |
Easy |
|
|
| 227 |
Basic Calculator II |
Stack |
O(n) |
O(1) |
Medium |
|
|
| 228 |
Summary Ranges |
Array |
O(n) |
O(n) |
Medium |
|
|
| 229 |
Majority Element II |
Math |
O(n) |
O(1) |
Medium |
|
|
| 230 |
Kth Smallest Element in a BST |
Tree |
O(n) |
O(1) |
Medium |
|
|
| 231 |
Power of Two |
Bit Manipulation |
O(1) |
O(1) |
Easy |
|
|
| 232 |
Implement Queue using Stacks |
Stack |
O(1) |
O(1) |
Easy |
|
|
| 233 |
Number of Digit One |
Recursion |
O(n) |
O(1) |
Hard |
|
|
| 234 |
Palindrome Linked List |
Linked List |
O(n) |
O(1) |
Easy |
|
|
| 235 |
Lowest Common Ancestor of a Binary Search Tree |
Tree |
O(n) |
O(1) |
Easy |
|
|
| 236 |
Lowest Common Ancestor of a Binary Tree |
Tree |
O(n) |
O(1) |
Medium |
Y |
|
| 237 |
Delete Node in a Linked List |
Linked List |
O(1) |
O(1) |
Easy |
|
|
| 238 |
Product of Array Except Self |
DP |
O(n) |
O(n) |
Medium |
|
|
| 239 |
Sliding Window Maximum |
Queue |
O(n) |
O(n) |
Hard |
Y |
|
| 240 |
Search a 2D Matrix II |
Search |
O(n) |
O(1) |
Medium |
|
|
| 241 |
Different Ways to Add Parentheses |
Recursion |
O(n^2) |
O(1) |
Medium |
Y |
|
| 242 |
Valid Anagram |
Hash Table |
O(n) |
O(1) |
Medium |
|
|
| 243 |
Shortest Word Distance |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 244 |
Shortest Word Distance II |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 245 |
Shortest Word Distance III |
Array |
O(n) |
O(1) |
Medium |
|
|
| 246 |
Strobogrammatic Number |
Hash Table |
O(n) |
O(1) |
Easy |
|
|
| 247 |
Strobogrammatic Number II |
Recursion |
O(n!) |
O(1) |
Medium |
Y |
|
| 248 |
Strobogrammatic Number III |
Recursion |
O(n!) |
O(1) |
Hard |
|
|
| 249 |
Group Shifted Strings |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 250 |
Count Univalue Subtrees |
Recursion |
O(n) |
O(1) |
Medium |
|
|
| 251 |
Flatten 2D Vector |
Math |
O(1) |
O(1) |
Medium |
|
|
| 252 |
Meeting Rooms |
Sort |
O(nlogn) |
O(1) |
Easy |
|
|
| 253 |
Meeting Rooms II |
Greedy + Sort |
O(nlogn) |
O(n) |
Medium |
Y |
|
| 254 |
Factor Combinations |
BackTracking |
O(n!) |
O(1) |
Medium |
Y |
|
| 255 |
Verify Preorder Sequence in Binary Search Tree |
Stack |
O(n!) |
O(n) |
Medium |
|
|
| 256 |
Paint House |
DP |
O(n) |
O(n) |
Easy |
|
|
| 257 |
Binary Tree Paths |
BackTracking |
O(n) |
O(1) |
Easy |
|
|
| 258 |
Add Digits |
Math |
O(1) |
O(1) |
Easy |
|
|
| 259 |
3Sum Smaller |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 260 |
Single Number III |
Bit Manipulation |
O(n) |
O(1) |
Medium |
|
|
| 261 |
Graph Valid Tree |
DFS |
O(n) |
O(n) |
Medium |
Y |
find cycle |
| 263 |
Ugly Number |
Math |
O(1) |
O(1) |
Easy |
|
|
| 264 |
Ugly Number II |
Math |
O(n) |
O(1) |
Medium |
|
|
| 265 |
Paint House II |
DP |
O(n) |
O(n) |
Hard |
|
|
| 266 |
Palindrome Permutation |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 267 |
Palindrome Permutation II |
Back Tracking |
O(n!) |
O(1) |
Medium |
Y |
|
| 268 |
Missing Number |
Math |
O(n) |
O(1) |
Easy |
|
|
| 269 |
Alien Dictionary |
Topological Sort |
O(n) |
O(n) |
Hard |
Y |
|
| 270 |
Closest Binary Search Tree Value |
Tree |
O(n) |
O(n) |
Easy |
|
|
| 271 |
Encode and Decode Strings |
String |
O(n) |
O(1) |
Medium |
|
|
| 272 |
Closest Binary Search Tree Value II |
Tree |
O(n) |
O(1) |
Hard |
|
|
| 273 |
Integer to English Words |
String |
O(n) |
O(1) |
Hard |
|
|
| 274 |
H-Index |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 275 |
H-Index II |
Binary Search |
O(logn) |
O(1) |
Medium |
|
|
| 276 |
Paint Fence |
DP |
O(n) |
O(1) |
Easy |
|
|
| 277 |
Find the Celebrity |
Array |
O(n) |
O(1) |
Medium |
|
|
| 278 |
First Bad Version |
Binary Search |
O(logn) |
O(1) |
Easy |
Y |
|
| 279 |
Perfect Squares |
DP |
O(n) |
O(n) |
Medium |
|
|
| 280 |
Wiggle Sort |
Sort |
O(n) |
O(1) |
Medium |
|
|
| 281 |
Zigzag Iterator |
Array |
O(1) |
O(1) |
Medium |
|
|
| 282 |
Expression Add Operators |
Divide n Conquer |
O(n!) |
O(1) |
Hard |
|
|
| 283 |
Move Zeroes |
Two Pointers |
O(n) |
O(1) |
Easy |
|
|
| 284 |
Peeking Iterator |
Design1 |Design2 |
O(1) |
O(1) |
Medium |
|
|
| 285 |
Inorder Successor in BST |
Tree |
O(n) |
O(1) |
Easy |
Y |
|
| 286 |
Walls and Gates |
BFS |
O(n) |
O(n) |
Medium |
Y |
|
| 287 |
Find the Duplicate Number |
Binary Search |
O(logn) |
O(1) |
Medium |
|
|
| 288 |
Unique Word Abbreviation |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 289 |
Game of Life |
DFS |
O(n!) |
O(1) |
Medium |
|
|
| 290 |
Word Pattern |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 291 |
Word Pattern II |
BackTracking |
O(n!) |
O(n) |
Hard |
Y |
|
| 292 |
Nim Game |
Math |
O(1) |
O(1) |
Easy |
|
|
| 293 |
Flip Game |
String |
O(n) |
O(1) |
Easy |
|
|
| 294 |
Flip Game II |
BackTracking |
O(n!) |
O(n) |
Medium |
|
|
| 295 |
Find Median from Data Stream |
Heap |
O(1) |
O(n) |
Hard |
Y |
|
| 296 |
Best Meeting Point |
Sort |
O(nlogn) |
O(1) |
Hard |
|
|
| 297 |
Serialize and Deserialize Binary Tree |
BackTracking |
O(n) |
O(1) |
Hard |
Y |
n-ary |
| 298 |
Binary Tree Longest Consecutive Sequence |
BackTracking |
O(n) |
O(1) |
Medium |
|
|
| 299 |
Bulls and Cows |
Hash Table |
O(n) |
O(1) |
Medium |
|
|
| 300 |
Longest Increasing Subsequence |
DP |
O(n) |
O(n) |
Medium |
|
|
| 301 |
Remove Invalid Parentheses |
BFS |
O(n) |
O(n) |
Hard |
|
Y |
| 302 |
Smallest Rectangle Enclosing Black Pixels |
Binary Search |
O(logn) |
O(1) |
Hard |
Y |
|
| 303 |
Range Sum Query - Immutable |
DP |
O(n) |
O(n) |
Easy |
|
|
| 304 |
Range Sum Query 2D - Immutable |
DP |
O(m*n) |
O(m*n) |
Medium |
|
|
| 305 |
Number of Islands II |
Union Find |
O(n) |
O(m*n) |
Hard |
Y |
|
| 306 |
Additive Number |
BackTracking |
O(n!) |
O(1) |
Medium |
|
|
| 307 |
Range Sum Query - Mutable |
BIT |Segment Tree |
O(n) |
O(n) |
Medium |
Y |
|
| 308 |
Range Sum Query 2D - Mutable |
BIT |Segment Tree |
O(m*n) |
O(m*n) |
Hard |
|
|
| 309 |
Best Time to Buy and Sell Stock with Cooldown |
DP |
O(n) |
O(n) |
Medium |
Y |
|
| 310 |
Minimum Height Trees |
Topological Sort |
O(n) |
O(n) |
Medium |
|
|
| 311 |
Sparse Matrix Multiplication |
Hash Table |
O(m*n) |
O(m*n) |
Medium |
Y |
|
| 312 |
Burst Balloons |
DP |
O(n^2) |
O(n^2) |
Hard |
|
|
| 313 |
Super Ugly Number |
Math |
O(n) |
O(m*n) |
Medium |
Y |
|
| 314 |
Binary Tree Vertical Order Traversal |
BFS |
O(n) |
O(n) |
Medium |
Y |
|
| 315 |
Count of Smaller Numbers After Self |
Binary Search |
O(nlogn) |
O(n) |
Hard |
|
|
| 316 |
Remove Duplicate Letters |
Greedy |
O(n) |
O(1) |
Hard |
|
|
| 317 |
Shortest Distance from All Buildings |
BFS |
O(n) |
O(n) |
Hard |
|
|
| 318 |
Maximum Product of Word Lengths |
Bit Manipulation |
O(m*n) |
O(n) |
Medium |
|
|
| 319 |
Bulb Switcher |
Math |
O(1) |
O(1) |
Medium |
|
|
| 320 |
Generalized Abbreviation |
BackTracking |
O(2^n) |
O(1) |
Medium |
Y |
|
| 321 |
Create Maximum Number |
Greedy |
O(n!) |
O(1) |
Hard |
|
|
| 322 |
Coin Change |
DP |
O(n) |
O(n) |
Medium |
|
|
| 323 |
Number of Connected Components in an Undirected Graph |
Union Find |
O(n) |
O(n) |
Medium |
Y |
|
| 324 |
Wiggle Sort II |
Sort |
O(nlog) |
O(n) |
Medium |
|
|
| 325 |
Maximum Size Subarray Sum Equals k |
Hash Table |
O(n) |
O(n) |
Medium |
Y |
|
| 326 |
Power of Three |
Math |
O(1) |
O(1) |
Easy |
Y |
|
| 327 |
Count of Range Sum |
Hash Table |
O(n) |
O(n) |
Hard |
|
|
| 328 |
Odd Even Linked List |
Linked List |
O(n) |
O(1) |
Medium |
|
|
| 329 |
Longest Increasing Path in a Matrix |
DFS |
O(n!) |
O(n^2) |
Hard |
|
|
| 330 |
Patching Array |
Greedy |
O(n) |
O(1) |
Hard |
|
|
| 331 |
Verify Preorder Serialization of a Binary Tree |
Sort |
O(n) |
O(1) |
Medium |
|
|
| 332 |
Reconstruct Itinerary |
DFS |
O(n!) |
O(n) |
Medium |
Y |
|
| 333 |
Largest BST Subtree |
DFS |
O(n) |
O(1) |
Medium |
|
|
| 334 |
Increasing Triplet Subsequence |
Array |
O(n) |
O(1) |
Medium |
|
|
| 335 |
Self Crossing |
Math |
O(n) |
O(1) |
Hard |
|
|
| 336 |
Palindrome Pairs |
Hash Table |
O(m*n) |
O(m) |
Hard |
|
|
| 337 |
House Robber III |
DFS |
O(n) |
O(1) |
Medium |
|
|
| 338 |
Counting Bits |
Bit Manipulation |
O(n) |
O(1) |
Medium |
|
|
| 339 |
Nested List Weight Sum |
DFS |
O(2^n) |
O(1) |
Easy |
|
|
| 340 |
Longest Substring with At Most K Distinct Characters |
Hash Table |
O(n) |
O(256) |
Hard |
|
|
| 341 |
Flatten Nested List Iterator |
Stack |
O(n) |
O(n) |
Medium |
Y |
|
| 342 |
Power of Four |
Math |
O(1) |
O(1) |
Easy |
|
|
| 343 |
Integer Break |
Math |
O(1) |
O(1) |
Medium |
|
|
| 344 |
Reverse String |
String |
O(n) |
O(1) |
Easy |
|
|
| 345 |
Reverse Vowels of a String |
String |
O(n) |
O(1) |
Easy |
|
|
| 346 |
Moving Average from Data Stream |
Queue |
O(1) |
O(n) |
Easy |
|
|
| 347 |
Top K Frequent Elements |
Heap |
O(n) |
O(n) |
Medium |
|
|
| 348 |
Design Tic-Tac-Toe |
Design |
O(1) |
O(n) |
Medium |
|
|
| 349 |
Intersection of Two Arrays |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 350 |
Intersection of Two Arrays II |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 351 |
Android Unlock Patterns |
DFS |
O(n!) |
O(n) |
Medium |
|
|
| 352 |
Data Stream as Disjoint Intervals |
Array |
O(n) |
O(n) |
Hard |
|
|
| 353 |
Design Snake Game |
Queue |
O(n) |
O(n) |
Medium |
|
|
| 354 |
Russian Doll Envelopes |
DP |
O(n) |
O(n) |
Hard |
|
|
| 355 |
Design Twitter |
Hash Table + Heap |
O(m*n) |
O(n) |
Medium |
Y |
|
| 356 |
Line Reflection |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 357 |
Count Numbers with Unique Digits |
Math |
O(n) |
O(1) |
Medium |
|
|
| 358 |
Rearrange String k Distance Apart |
Greedy |
O(n!) |
O(n) |
Hard |
|
|
| 359 |
Logger Rate Limiter |
Hash Table |
O(1) |
O(n) |
Easy |
Y |
|
| 360 |
Sort Transformed Array |
Two Pointers |
O(n) |
O(1) |
Medium |
|
|
| 361 |
Bomb Enemy |
DP |
O(m*n) |
O(m*n) |
Medium |
|
|
| 362 |
Design Hit Counter |
Queue | Circular Array |
O(n) |
O(n) |
Medium |
Y |
|
| 363 |
Max Sum of Rectangle No Larger Than K |
Hash Table |
O(col*col*row) |
O(row) |
Hard |
|
|
| 364 |
Nested List Weight Sum II |
DFS |
O(2^n) |
O(1) |
Medium |
|
|
| 365 |
Water and Jug Problem |
Math |
O(n) |
O(1) |
Medium |
|
gcd |
| 366 |
Find Leaves of Binary Tree |
Tree |
O(n) |
O(1) |
Medium |
|
|
| 367 |
Valid Perfect Square |
Binary Search |
O(logn) |
O(1) |
Easy |
|
|
| 368 |
Largest Divisible Subset |
DP |
O(ologn) |
O(n) |
Medium |
|
|
| 369 |
Plus One Linked List |
Recursion |
O(n) |
O(n) |
Medium |
Y |
|
| 370 |
Range Addition |
Array |
O(n) |
O(1) |
Medium |
|
|
| 371 |
Sum of Two Integers |
Bit Manipulation |
O(1) |
O(1) |
Easy |
|
|
| 372 |
Super Pow |
Math |
O(m*n) |
O(1) |
Medium |
|
|
| 373 |
Find K Pairs with Smallest Sums |
Heap |
O(m*n) |
O(m*n) |
Medium |
|
|
| 374 |
Guess Number Higher or Lower |
Binary Search |
O(logn) |
O(1) |
Easy |
|
|
| 375 |
Guess Number Higher or Lower II |
DP |
O(n^3) |
O(n^2) |
Medium |
|
|
| 376 |
Wiggle Subsequence |
Greedy |
O(n) |
O(1) |
Medium |
|
|
| 377 |
Combination Sum IV |
DP |
O(n) |
O(n) |
Medium |
|
|
| 378 |
Kth Smallest Element in a Sorted Matrix |
Heap |
O(n) |
O(n) |
Medium |
|
Y |
| 379 |
Design Phone Directory |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 380 |
Insert Delete GetRandom O(1) |
Hash Table |
O(1) |
O(n) |
Medium |
Y |
|
| 381 |
Insert Delete GetRandom O(1) - Duplicates allowed |
Hash Table |
O(1) |
O(n) |
Hard |
|
|
| 382 |
Linked List Random Node |
Math |
O(n) |
O(1) |
Medium |
Y |
蓄水池采样 |
| 383 |
Ransom Note |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 384 |
Shuffle an Array |
Math |
O(n) |
O(1) |
Medium |
|
|
| 385 |
Mini Parser |
Stack |
O(n) |
O(n) |
Medium |
|
Y |
| 386 |
Lexicographical Numbers |
String |
O(n) |
O(1) |
Medium |
|
|
| 387 |
First Unique Character in a String |
Hash Table |
O(n) |
O(256) |
Easy |
|
|
| 388 |
Longest Absolute File Path |
String |
O(n) |
O(n) |
Medium |
|
|
| 389 |
Find the Difference |
Bit Manipulation |
O(n) |
O(1) |
Easy |
|
|
| 390 |
Elimination Game |
Math |
O(n) |
O(1) |
Medium |
|
|
| 391 |
Perfect Rectangle |
Math |
O(n) |
O(n) |
Hard |
|
|
| 392 |
Is Subsequence |
Greedy |
O(n) |
O(n) |
Medium |
|
|
| 393 |
UTF-8 Validation |
Bit Manipulation |
O(n) |
O(1) |
Medium |
|
|
| 394 |
Decode String |
Stack |
O(n) |
O(n) |
Medium |
Y |
|
| 395 |
Longest Substring with At Least K Repeating Characters |
BackTracking |
O(2^n) |
O(1) |
Medium |
|
|
| 396 |
Rotate Function |
Math |
O(n) |
O(1) |
Medium |
|
|
| 397 |
Integer Replacement |
Backtracking |
O(2^n) |
O(1) |
Medium |
|
|
| 398 |
Random Pick Index |
Math |
O(n) |
O(1) |
Medium |
|
|
| 399 |
Evaluate Division |
DFS |
O(n!) |
O(1) |
Medium |
|
Y |
| 400 |
Nth Digit |
Math |
O(n) |
O(1) |
Easy |
|
|
| 401 |
Binary Watch |
Bit Manipulation |
O(720) |
O(1) |
Easy |
|
|
| 402 |
Remove K Digits |
Greedy |
O(n) |
O(n) |
Medium |
|
|
| 403 |
Frog Jump |
DP |
O(n) |
O(n) |
Hard |
|
|
| 404 |
Sum of Left Leaves |
Backtracking |
O(n) |
O(1) |
Easy |
|
|
| 405 |
Convert a Number to Hexadecimal |
Bit Manipulation |
O(n) |
O(1) |
Easy |
|
|
| 406 |
Queue Reconstruction by Height |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 407 |
Trapping Rain Water II |
BFS |
O(n) |
O(n) |
Hard |
|
|
| 408 |
Valid Word Abbreviation |
String |
O(n) |
O(1) |
Easy |
|
|
| 409 |
Longest Palindrome |
Hash Table |
O(n) |
O(256) |
Easy |
|
|
| 410 |
Split Array Largest Sum |
Binary Search |
O(logn) |
O(1) |
Hard |
|
|
| 411 |
Minimum Unique Word Abbreviation |
Backtracking |
O(2^n) |
O(1) |
Hard |
|
|
| 412 |
Fizz Buzz |
Array |
O(n) |
O(1) |
Easy |
|
|
| 413 |
Arithmetic Slices |
DP |
O(n) |
O(n) |
Medium |
|
|
| 414 |
Third Maximum Number |
Array |
O(n) |
O(1) |
Easy |
|
|
| 415 |
Add Strings |
Math |
O(n) |
O(n) |
Easy |
|
|
| 416 |
Partition Equal Subset Sum |
DP |
O(n) |
O(n) |
Medium |
|
|
| 417 |
Pacific Atlantic Water Flow |
DFS |
O(2^n) |
O(m*n) |
Medium |
|
|
| 418 |
Sentence Screen Fitting |
Hash Table |
O(n) |
O(n) |
Medium |
|
|
| 419 |
Battleships in a Board |
Math |
O(m*n) |
O(1) |
Medium |
|
|
| 420 |
Strong Password Checker |
Hash Table |
O(n) |
O(1) |
Hard |
|
|
| 421 |
Maximum XOR of Two Numbers in an Array |
Bit Manipulation + Trie |
O(n) |
O(n) |
Medium |
|
|
| 422 |
Valid Word Square |
String |
O(n*k) |
O(1) |
Easy |
|
|
| 423 |
Reconstruct Original Digits from English |
Math |
O(n) |
O(n) |
Medium |
|
|
| 424 |
Longest Repeating Character Replacement |
String |
O(n) |
O(n) |
Medium |
|
|
| 425 |
Word Squares |
Backtracking + Trie |
O(n!) |
O(n) |
Hard |
Y |
|
| 432 |
All O one Data Structure |
Hash Table |
O(1) |
O(n) |
Hard |
Y |
|
| 434 |
Number of Segments in a String |
String |
O(n) |
O(1) |
Easy |
|
|
| 435 |
Non-overlapping Intervals |
Greedy |
O(nlogn) |
O(1) |
Medium |
|
|
| 436 |
Find Right Interval |
Binary Search |
O(nlogn) |
O(n) |
Medium |
|
|
| 437 |
Path Sum III |
Backtracking |
O(n) |
O(1) |
Easy |
|
|
| 438 |
Find All Anagrams in a String |
Hash Table |
O(n) |
O(26) |
Easy |
|
|
| 439 |
Ternary Expression Parser |
Stack |
O(n) |
O(n) |
Medium |
|
|
| 440 |
K-th Smallest in Lexicographical Order |
Tree |
O(logn*k) |
O(n) |
Hard |
|
|
| 441 |
Arranging Coins |
Binary Search |
O(logn) |
O(1) |
Easy |
Y |
|
| 442 |
Find All Duplicates in an Array |
Array |
O(n) |
O(1) |
Medium |
|
|
| 444 |
Sequence Reconstruction |
Hash Table |
O(m*n) |
O(n) |
Medium |
|
|
| 445 |
Add Two Numbers II |
Stack |
O(n) |
O(n) |
Medium |
|
|
| 446 |
Arithmetic Slices II - Subsequence |
DP |
O(n) |
O(n) |
Hard |
|
|
| 447 |
Number of Boomerangs |
Hash Table |
O(n^2) |
O(n) |
Easy |
|
|
| 448 |
Find All Numbers Disappeared in an Array |
Array |
O(n) |
O(1) |
Easy |
|
|
| 449 |
Serialize and Deserialize BST |
Tree |
O(n) |
O(n) |
Hard |
|
|
| 450 |
Delete Node in a BST |
Tree |
O(n) |
O(1) |
Medium |
|
|
| 451 |
Sort Characters By Frequency |
Heap |
O(n) |
O(n) |
Medium |
|
|
| 452 |
Minimum Number of Arrows to Burst Balloons |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 453 |
Minimum Moves to Equal Array Elements |
Array |
O(n) |
O(1) |
Easy |
|
|
| 454 |
4Sum II |
Math |
O(n^2) |
O(n) |
Medium |
|
|
| 455 |
Assign Cookies |
Greedy |
O(nlogn) |
O(n) |
Easy |
|
|
| 456 |
132 Pattern |
Array |
O(n^2) |
O(n) |
Medium |
|
|
| 459 |
Repeated Substring Pattern |
String |
O(n^2) |
O(1) |
Easy |
|
|
| 460 |
LFU Cache |
Design |
O(n) |
O(n) |
Hard |
|
|
| 461 |
Hamming Distance |
Bit Manipulation |
O(n) |
O(1) |
Easy |
|
|
| 462 |
Minimum Moves to Equal Array Elements II |
Sort |
O(nlogn) |
O(1) |
Medium |
|
|
| 463 |
Island Perimeter |
Math |
O(m*n) |
O(1) |
Easy |
|
|
| 464 |
Can I Win |
BackTracking |
O(n!) |
O(n) |
Medium |
|
|
| 465 |
Optimal Account Balancing |
BackTracking |
O(n!) |
O(n) |
Hard |
Y |
|
| 466 |
Count The Repetitions |
DP |
O(n) |
O(n) |
Hard |
|
|
| 467 |
Unique Substrings in Wraparound String |
DP |
O(n) |
O(n) |
Medium |
|
|
| 468 |
Validate IP Address |
String |
O(n) |
O(1) |
Medium |
|
|
| 469 |
Convex Polygon |
Math |
O(n) |
O(1) |
Medium |
|
|
| 471 |
Encode String with Shortest Length |
DP |
O(n^2) |
O(1) |
Hard |
|
|
| 472 |
Concatenated Words |
DP |
O(m*n) |
O(n) |
Hard |
|
|
| 473 |
Matchsticks to Square |
BackTracking |
O(n!) |
O(1) |
Medium |
|
|
| 474 |
Ones and Zeroes |
DP |
O(m*n) |
O(m*n) |
Medium |
|
|
| 475 |
Heaters |
Binary Search |
O(nlogn) |
O(1) |
Easy |
|
|
| 476 |
Number Complement |
Bit Manipulation |
O(n) |
O(1) |
Easy |
|
|
| 477 |
Total Hamming Distance |
Bit Manipulation |
O(n) |
O(1) |
Medium |
|
|
| 480 |
Sliding Window Median |
Heap |
O(1) |
O(n) |
Hard |
Y |
multiset |
| 481 |
Magical String |
Math |
O(n) |
O(n) |
Medium |
|
|
| 482 |
License Key Formatting |
String |
O(n) |
O(1) |
Medium |
|
|
| 483 |
Smallest Good Base |
Binary Search |
O(logn) |
O(1) |
Hard |
|
|
| 484 |
Find Permutation |
Greedy |
O(n) |
O(n) |
Medium |
|
|
| 485 |
Max Consecutive Ones |
Array |
O(n) |
O(1) |
Easy |
|
|
| 486 |
Predict the Winner |
Backtracking |
O(2^n) |
O(1) |
Medium |
|
|
| 487 |
Max Consecutive Ones II |
Array |
O(n) |
O(1) |
Medium |
Y |
sliding window |
| 490 |
The Maze |
DFS | BFS |
O(n) |
O(n) |
Medium |
Y |
|
| 491 |
Increasing Subsequences |
Backtracking |
O(n!) |
O(1) |
Medium |
|
|
| 492 |
Construct the Rectangle |
Math |
O(n^0.5) |
O(1) |
Easy |
|
|
| 494 |
Target Sum |
Backtracking |
O(2^n) |
O(1) |
Medium |
|
|
| 495 |
Teemo Attacking |
Array |
O(n) |
O(1) |
Medium |
|
|
| 496 |
Next Greater Element I |
Hash Table |
O(n) |
O(n) |
Easy |
|
|
| 498 |
Diagonal Traverse |
Solution |
O(m*n) |
O(1) |
Medium |
|
|
| 499 |
The Maze III |
DFS |
O(n!) |
O(m*n) |
Hard |
|
|
| 500 |
Keyboard Row |
Hash Table |
O(n) |
O(1) |
Easy |
|
|