840. Magic Squares In Grid(#1 ).java

class Solution {
    public int numMagicSquaresInside(int[][] grid) {
        if (grid == null || grid.length < 3 || grid[0].length < 3) return 0;
        
        int m = grid.length, n = grid[0].length;
        boolean[] visited = new boolean[9];
        int[] rows = new int[3];
        int[] cols = new int[3];
        int[] diags = new int[2];
        boolean flag = false;
        int count = 0;
        for (int i = 0; i <= m - 3; i++) {
            for (int j = 0; j <= n - 3; j++) {
                for (int r = 0; r < 3; r++) {
                    for (int l = 0; l < 3; l++) {
                        int cur = grid[r + i][l + j];
        
                        if ((cur <= 9 && cur >= 1 ) && !visited[cur - 1]) {
                            rows[r] += cur;
                            cols[l] += cur;
                            if (r == l) diags[0] += cur;
                            if (r + l == 2) diags[1] += cur;
                        } else {
                            flag = true;
                            break;
                        }
                        
                    }
                    if (flag) break;
                }
                if (!flag) {
                    int first = rows[0];
                    boolean equal = true;
                    for (int ii = 0; ii < 3; ii++) {
                        if (rows[ii] != first || cols[ii] != first) {
                            equal = false;
                            break;
                        }
                    }
                    if (diags[0] != first || diags[1] != first) {
                        equal = false;
                    }
                    if (equal) count++;
                }
                rows = new int[3];
                cols = new int[3];
                diags = new int[2];
                flag = false;
            }
        }
        return count;
    }
}840. Magic Squares In Grid