public int countCornerRectangles(int[][] grid) {

int M = grid.length;

int N = grid[0].length;

int res = 0;

for (int i=0; i<M-1; i++) {

for (int j=0; j<N-1; j++) {

if (grid[i][j] == 0) continue;

for (int p=i+1; p<M; p++) {

if (grid[p][j] == 0) continue;

for (int q=j+1; q<N; q++) {

if (grid[i][q] == 0) continue;

if (grid[p][q] == 1) res++;

}

}

}

}

return res;

}

/**

public int countCornerRectangles2(int[][] grid) {

Map<Integer, Integer> count = new HashMap();

int ans = 0;

for (int[] row: grid) {

for (int c1 = 0; c1 < row.length; ++c1) if (row[c1] == 1) {

for (int c2 = c1+1; c2 < row.length; ++c2) if (row[c2] == 1) {

int pos = c1 * 200 + c2;

int c = count.getOrDefault(pos, 0);

ans += c;

count.put(pos, c+1);

}

}

}

return ans;

}

/**

public int countCornerRectangles3(int[][] grid) {

int ans = 0;

for (int i = 0; i < grid.length - 1; i++) {

for (int j = i + 1; j < grid.length; j++) {

int counter = 0;

for (int k = 0; k < grid[0].length; k++) {

if (grid[i][k] == 1 && grid[j][k] == 1) counter++;

}

if (counter > 0) ans += counter * (counter - 1) / 2;

}

}

return ans;

}

/**

public int countCornerRectangles4(int[][] grid) {

int m = grid.length, n = grid[0].length, res = 0;

int[][] dp = new int[n][n];

for (int i = 0; i < m; i++) {

for (int j = 0; j < n; j++) {

if (grid[i][j] == 0) continue;

for (int q = j + 1; q < n; q++) {

if (grid[i][q] == 0) continue;

res += dp[j][q]++;

}

}

}

return res;

}