matrixrotationpossible.java

class Solution {
    public boolean findRotation(int[][] mat, int[][] target) {
        int n = mat.length;
        for (int k = 0; k < 4; k++) { 
            if (isEqual(mat, target)) {
                return true;
            }
            rotate90(mat);
        }
        return false;
    }
    private void rotate90(int[][] mat) {
        int n = mat.length;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                int temp = mat[i][j];
                mat[i][j] = mat[j][i];
                mat[j][i] = temp;
            }
        }
        for (int i = 0; i < n; i++) {
            reverseRow(mat[i]);
        }
    }
    private void reverseRow(int[] row) {
        int left = 0, right = row.length - 1;
        while (left < right) {
            int temp = row[left];
            row[left] = row[right];
            row[right] = temp;
            left++;
            right--;
        }
    }
    private boolean isEqual(int[][] mat, int[][] target) {
        for (int i = 0; i < mat.length; i++) {
            for (int j = 0; j < mat[0].length; j++) {
                if (mat[i][j] != target[i][j]) {
                    return false;
                }
            }
        }
        return true;
    }
}