Rotate by 90 Degrees Counter-Clockwise - Amazon Top Interview Questions

                        Solution in C++ :

void modify(int pos, vector<vector<int>>& matrix) {
    int n = matrix.size();
    for (int i = 0; i < n - 2 * pos - 1; ++i) {
        int tmp = matrix[n - 1 - pos - i][pos], tmp1;
        swap(matrix[pos][pos + i], matrix[n - 1 - pos - i][pos]);
        swap(tmp, matrix[n - 1 - pos][n - 1 - pos - i]);
        swap(tmp, matrix[pos + i][n - 1 - pos]);
        swap(tmp, matrix[pos][pos + i]);
    }
}

vector<vector<int>> solve(vector<vector<int>>& matrix) {
    for (int i = 0, n = matrix.size(); n > 1; i++, n -= 2) {
        modify(i, matrix);
    }

    return matrix;
}
                    

                        Solution in Java :

import java.util.*;

class Solution {
    public int[][] solve(int[][] matrix) {
        for (int[] row : matrix) {
            reverse(row);
        }
        int n = matrix.length;
        int m = matrix[0].length;

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < i; j++) {
                int tmp = matrix[i][j];
                matrix[i][j] = matrix[j][i];
                matrix[j][i] = tmp;
            }
        }
        return matrix;
    }

    private void reverse(int[] arr) {
        int i = 0;
        int j = arr.length - 1;
        while (i < j) {
            int tmp = arr[i];
            arr[i] = arr[j];
            arr[j] = tmp;
            i++;
            j--;
        }
    }
}
                    

                        Solution in Python : 
                            
class Solution:
    def solve(self, matrix):

        for i in range(0, len(matrix)):
            for j in range(i, len(matrix)):
                matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]

        for i in range(0, len(matrix) // 2):
            matrix[i], matrix[len(matrix) - i - 1] = matrix[len(matrix) - i - 1], matrix[i]

        return matrix