看代码：

class Solution {
public:
    bool isRectangleOverlap(vector<int>& rec1, vector<int>& rec2) {
        int x1 = max(rec1[0], rec2[0]), y1 = max(rec1[1], rec2[1]);
        int x2 = min(rec1[2], rec2[2]), y2 = min(rec1[3], rec2[3]);
        if(x1 >= x2 || y1 >= y2) return false;
        return true;
    }
};