int m = mat.size(); int n = mat[0].size(); int row = 0, col = 0; int prev, curr; // Rotate the matrix in layers while (row < m && col < n) { if (row + 1 == m || col + 1 == n) break; // Store the first element of the next row prev = mat[row + 1][col]; // Move elements of the first row for (int i = col; i < n; i++) { curr = mat[row][i]; mat[row][i] = prev; prev = curr; } row++; // Move elements of the last column for (int i = row; i < m; i++) { curr = mat[i][n - 1]; mat[i][n - 1] = prev; prev = curr; } n--; // Move elements of the last row if (row < m) { for (int i = n - 1; i >= col; i--) { curr = mat[m - 1][i]; mat[m - 1][i] = prev; prev = curr; } } m--; // Move elements of the first column if (col < n) { for (int i = m - 1; i >= row; i--) { curr = mat[i][col]; mat[i][col] = prev; prev = curr; } } col++; } } int main() { vector> mat = { {1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16} }; rotateMatrix(mat); // Print the rotated matrix for (auto& r : mat) { for (int val : r) cout << val << " "; cout << endl; } return 0; }