Repository of code challenges commonly encountered in developer interviews.
Problem Statement:
Determine if a string s that contains just the characters '(', ')', '{', '}', '[' and ']', is valid. A string is valid if:
- Open brackets are closed by the same type of brackets.
- Open brackets are closed in the correct order.
- Each close bracket has a corresponding open bracket of the same type.
Examples:
-
Input:
s = "()"
Output:true -
Input:
s = "()[]{}"
Output:true -
Input:
s = "(]"
Output:false
Problem Statement:
An array is a data structure that stores elements of the same type in a contiguous block of memory. Given an array A of size N, reverse the array.
Note: If you have already solved the Arrays Introduction challenge in our C++ domain, you may want to skip this.
Function Description:
Complete the function reverseArray as described below:
reverseArray(int A[n]): The array to reverse.
Returns:
int[n]: The reversed array.
Input Format:
- The first line contains an integer,
N, the number of integers inA. - The second line contains
Nspace-separated integers that make upA.
Examples:
- Input:
A = [1, 2, 3]
Return:[3, 2, 1]
Constraints:
1 ≤ N ≤ 10^31 ≤ A[i] ≤ 10^4, whereA[i]is theith integer inA.
Declare a 2-dimensional array, arr, of n empty arrays. All arrays are zero indexed. Declare an integer, lastAnswer, and initialize it to 0. There are 2 types of queries, given as an array of strings for you to parse: Query: 1 x y Let idx = ((x XOR lastAnswer) % n). Append the integer y to arr[idx]. Query: 2 x y Let idx = ((x XOR lastAnswer) % n). Assign the value arr[idx][y % size(arr[idx])] to lastAnswer. Store the new value of lastAnswer to an answers array. Note: ^ is the bitwise XOR operation, which corresponds to the ^ operator in most languages. Learn more about it on Wikipedia. % is the modulo operator. Finally, size(arr[idx]) is the number of elements in arr[idx]
Function Description
Complete the dynamicArray function below.
dynamicArray has the following parameters:
int n: the number of empty arrays to initialize in arr string queries[q]: query strings that contain 3 space-separated integers Returns
int[]: the results of each type 2 query in the order they are presented Input Format
The first line contains two space-separated integers, n, the size of arr to create, and q, the number of queries, respectively. Each of the q subsequent lines contains a query string, queries[i].
Constraints
1 <= n, q <= 10^5 0 <= x, y <= 10^9 It is guaranteed that query type 2 will never query an empty array or index.
Sample Input
2 5 1 0 5 1 1 7 2 0 1 2 1 0 1 0 3
Output
7 3
A left rotation operation on an array of size n shifts each of the array's elements 1 unit to the left. Given an integer, d, rotate the array that many steps left and return the result.
Example
d = 2
arr = [1, 2, 3, 4, 5]
After 2 rotations, arr' = [3, 4, 5, 1, 2].
Function Description
Complete the rotateLeft function in the editor below.
rotateLeft has the following parameters:
int d: the amount to rotate by int arr[n]: the array to rotate Returns
int[n]: the rotated array Input Format
The first line contains two space-separated integers that denote n, the number of integers, and d, the number of left rotations to perform. The second line contains n space-separated integers that describe arr[].
Constraints
1 ≤ n ≤ 10^5 1 ≤ d ≤ n 1 ≤ a[i] ≤ 10^6
Sample Input
5 4 1 2 3 4 5
Sample Output
5 1 2 3 4
Alice and Bob each created one problem for HackerRank. A reviewer rates the two challenges, awarding points on a scale from 1 to 100 for three categories: problem clarity, originality, and difficulty.
The rating for Alice's challenge is the triplet a = (a[0], a[1], a[2]), and the rating for Bob's challenge is the triplet b = (b[0], b[1], b[2]).
The task is to find their comparison points by comparing a[0] with b[0], a[1] with b[1], and a[2] with b[2].
If a[i] > b[i], then Alice is awarded 1 point. If a[i] < b[i], then Bob is awarded 1 point. If a[i] = b[i], then neither person receives a point. Comparison points is the total points a person earned.
Given a and b, determine their respective comparison points.
Example
a = [1, 2, 3] b = [3, 2, 1]
For elements 0, Bob is awarded a point because a[0] . For the equal elements a[1] and b[1], no points are earned. Finally, for elements 2, a[2] > b[2] so Alice receives a point. The return array is [1, 1], with Alice's score first and Bob's second.
Function Description
Complete the function compareTriplets in the editor below.
compareTriplets has the following parameter(s):
int a[3]: Alice's challenge rating int b[3]: Bob's challenge rating Return
int[2]: Alice's score is in the first position, and Bob's score is in the second. Input Format
The first line contains 3 space-separated integers, a[0], a[1], and a[2], the respective values in triplet a. The second line contains 3 space-separated integers, b[0], b[1], and b[2], the respective values in triplet b.
Constraints
1 ≤ a[i] ≤ 100 1 ≤ b[i] ≤ 100
Sample Input 0
5 6 7 3 6 10
Sample Output 0
1 1
Explanation 0
In this example:
a = (a[0], a[1], a[2]) = (5, 6, 7) b = (b[0], b[1], b[2]) = (3, 6, 10) Now, let's compare each individual score:
a[0] > b[0], so Alice receives 1 point. a[1] = b[1], so nobody receives a point. a[2] < b[2], so Bob receives 1 point. Alice's comparison score is 1, and Bob's comparison score is 1. Thus, we return the array [1, 1].
Sample Input 1
17 28 30 99 16 8
Sample Output 1
2 1
Explanation 1
Comparing the 0th elements, 17 < 99 so Bob receives a point. Comparing the 1st and 2nd elements, 28 > 16 and 30 > 8 so Alice receives two points. The return array is [2, 1].