/leetcode

The journey of grinding leetcode

Primary LanguageC++

leetcode

The journey of grinding LeetCode.

Top Liked Questions

# Title Difficulty Completed
617 Merge Two Binary Trees Easy V
104 Maximum Depth of Binary Tree Easy V
136 Single Number Easy V
226 Invert Binary Tree Easy V
206 Reverse Linked List Easy V
283 Move Zeroes Easy V
169 Majority Element Easy V
448 Find All Numbers Disappeared in an Array Easy V
21 Merge Two Sorted Lists Easy V
121 Best Time to Buy and Sell Stock Easy V
543 Diameter of Binary Tree Easy V
70 Climbing Stairs Easy V
53 Maximum Subarray Easy V
101 Symmetric Tree Easy V
1 Two Sum Easy V
437 Path Sum III Easy V
198 House Robber Easy V
155 Min Stack Easy V
141 Linked List Cycle Easy V
20 Valid Parentheses Easy V
234 Palindrome Linked List Easy V
160 Intersection of Two Linked Lists Easy V
581 Shortest Unsorted Continuous Subarray Easy V
338 Counting Bits Medium V
406 Queue Reconstruction by Height Medium V
739 Daily Temperatures Medium V
94 Binary Tree Inorder Traversal Medium V
46 Permutations Medium V
22 Generate Parentheses Medium V
647 Palindromic Substrings Medium V
347 Top K Frequent Elements Medium V
238 Product of Array Except Self Medium V
78 Subsets Medium V
48 Rotate Image Medium V
39 Combination Sum Medium V
49 Group Anagrams Medium V
287 Find the Duplicate Number Medium V
215 Kth Largest Element in an Array Medium V
102 Binary Tree Level Order Traversal Medium V
62 Unique Paths Medium V
64 Minimum Path Sum Medium V
337 House Robber III Medium V
96 Unique Binary Search Trees Medium V
11 Container With Most Water Medium V
394 Decode String Medium V
621 Task Scheduler Medium V
114 Flatten Binary Tree to Linked List Medium V
494 Target Sum Medium V
105 Construct Binary Tree from Preorder and Inorder Traversal Medium V
309 Best Time to Buy and Sell Stock with Cooldown Medium V
17 Letter Combinations of a Phone Number Medium V
200 Number of Islands Medium V
75 Sort Colors Medium V
279 Perfect Squares Medium V
208 Implement Trie (Prefix Tree) Medium V
560 Subarray Sum Equals K Medium V
236 Lowest Common Ancestor of a Binary Tree Medium V
240 Search a 2D Matrix II Medium V
416 Partition Equal Subset Sum Medium V
300 Longest Increasing Subsequence Medium V
207 Course Schedule Medium V
438 Find All Anagrams in a String Medium V
148 Sort List Medium V
139 Word Break Medium V
56 Merge Intervals Medium V
221 Maximal Square Medium V
142 Linked List Cycle II Medium V
34 Find First and Last Position of Element in Sorted Array Medium V
19 Remove Nth Node From End of List Medium V
79 Word Search Medium V
322 Coin Change Medium V
33 Search in Rotated Sorted Array Medium V
55 Jump Game Medium V
2 Add Two Numbers Medium V
138 Copy List with Random Pointer Medium V
31 Next Permutation Medium V
152 Maximum Product Subarray Medium V
146 LRU Cache Medium V
3 Longest Substring Without Repeating Characters Medium V
5 Longest Palindromic Substring Medium V
98 Validate Binary Search Tree Medium V
15 3Sum Medium V

Top Interview Questions(Easy)

# Title Difficulty Completed
344 Reverse String Easy V
104 Maximum Depth of Binary Tree Easy V
237 Delete Node in a Linked List Easy V
136 Single Number Easy V
206 Reverse Linked List Easy V
412 Fizz Buzz Easy V
108 Convert Sorted Array to Binary Search Tree Easy V
169 Majority Element Easy V
242 Valid Anagram Easy V
122 Best Time to Buy and Sell Stock II Easy V
283 Move Zeroes Easy V
171 Excel Sheet Column Number Easy V
13 Roman to Integer Easy V
217 Contains Duplicate Easy V
21 Merge Two Sorted Lists Easy V
118 Pascal's Triangle Easy V
268 Missing Number Easy V
191 Number of 1 Bits Easy V
387 First Unique Character in a String Easy V
350 Intersection of Two Arrays II Easy V
121 Best Time to Buy and Sell Stock Easy V
202 Happy Number Easy V
70 Climbing Stairs Easy V
101 Symmetric Tree Easy V
53 Maximum Subarray Easy V
26 Remove Duplicates from Sorted Array Easy V
1 Two Sum Easy V
155 Min Stack Easy V
160 Intersection of Two Linked Lists Easy V
141 Linked List Cycle Easy V
66 Plus One Easy V
190 Reverse Bits Easy V
326 Power of Three Easy V
88 Merge Sorted Array Easy V
234 Palindrome Linked List Easy V
20 Valid Parentheses Easy V
172 Factorial Trailing Zeroes Easy V
125 Valid Palindrome Easy V
14 Longest Common Prefix Easy V
28 Implement strStr() Easy V
69 Sqrt(x) Easy V
204 Count Primes Easy V
7 Reverse Integer Easy V
230 Kth Smallest Element in a BST Medium V

Essential Concepts

  • Data Structure:
    • String
    • Array
    • Tree
    • Hash Table
      • Chaining
      • Open Addressing
        • Linear Probing
        • Quadratic Hashing
        • Double Hashing
    • Stack
    • Queue
    • Linked List
    • Heap
    • Set
      • Ordered Set
      • UnOrdered Set
  • Problem Solving Techniques:
    • Divide and Conquer
    • Dynamic Programming: Top down / Bottom Up
    • Backtracking
    • Recursion
    • Two Pointers
    • Binary Search
  • Tree Traversal (Recursive/Iterative)
  • Search:
    • Binary Search
    • DFS
    • BFS
    • KMP (Knuth–Morris–Pratt algorithm, for string matching)
  • Sort:
    • Selection Sort
    • Insertion Sort
    • Bubble Sort
    • Quick Sort
    • Merge Sort
    • Heap Sort
  • Graph:
    • Shortest Path
    • Cycle Detection (directed / undirected)
  • Bit Manipulation
  • Object Oriented Programming
    • Class & Object
    • Access Modifier: public, protected, private
    • Constructor
    • Encapsulation
    • Abstraction
    • Inheritance
    • Polymorphism