# leetcode\_836

A rectangle is represented as a list \[x1, y1, x2, y2], where (x1, y1) are the coordinates of its bottom-left corner, and (x2, y2) are the coordinates of its top-right corner.

Two rectangles overlap if the area of their intersection is positive. To be clear, two rectangles that only touch at the corner or edges do not overlap.

Given two (axis-aligned) rectangles, return whether they overlap.

Example 1:

Input: rec1 = \[0,0,2,2], rec2 = \[1,1,3,3] Output: true Example 2:

Input: rec1 = \[0,0,1,1], rec2 = \[1,0,2,1] Output: false Notes:

Both rectangles rec1 and rec2 are lists of 4 integers. All coordinates in rectangles will be between -10^9 and 10^9.

## Solutions

1. **straight forward**
2. Check nonoverlap.

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

or check overlap.

```cpp
class Solution {
public:
    bool isRectangleOverlap(vector<int>& rec1, vector<int>& rec2) {
        return min(rec1[2], rec2[2]) > max(rec1[0], rec2[0]) &&
               min(rec1[3], rec2[3]) > max(rec1[1], rec2[1]);
    }
};
```