Solution.java

class Solution {
    public int maxRectangleArea(int[][] points) {
        int ans = -1;
        for (int i = 0; i < points.length; ++i) {
            int x1 = points[i][0], y1 = points[i][1];
            for (int j = 0; j < i; ++j) {
                int x2 = points[j][0], y2 = points[j][1];
                int x3 = Math.min(x1, x2), y3 = Math.min(y1, y2);
                int x4 = Math.max(x1, x2), y4 = Math.max(y1, y2);
                if (check(points, x3, y3, x4, y4)) {
                    ans = Math.max(ans, (x4 - x3) * (y4 - y3));
                }
            }
        }
        return ans;
    }

    private boolean check(int[][] points, int x1, int y1, int x2, int y2) {
        int cnt = 0;
        for (var p : points) {
            int x = p[0];
            int y = p[1];
            if (x < x1 || x > x2 || y < y1 || y > y2) {
                continue;
            }
            if ((x == x1 || x == x2) && (y == y1 || y == y2)) {
                cnt++;
                continue;
            }
            return false;
        }
        return cnt == 4;
    }
}