836. Rectangle Overlap.cpp

An axis-aligned rectangle is represented as a list [x1, y1, x2, y2], 
where (x1, y1) is the coordinate of its bottom-left corner, and (x2, y2) 
is the coordinate of its top-right corner. Its top and bottom edges are 
parallel to the X-axis, and its left and right edges are parallel to the Y-axis.

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 rec1 and rec2, return true if they overlap, 
otherwise return false.

 

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
Example 3:

Input: rec1 = [0,0,1,1], rec2 = [2,2,3,3]
Output: false
 

Constraints:

rect1.length == 4
rect2.length == 4
-109 <= rec1[i], rec2[i] <= 109
rec1 and rec2 represent a valid rectangle with a non-zero area.










class Solution {
public:
    bool isRectangleOverlap(vector<int>& rec1, vector<int>& rec2) {
        if(rec1[2] <= rec2[0] ||   // rec1 is left of rec2
            rec1[0] >= rec2[2] ||  // rec1 is right of rec2
            rec1[1] >= rec2[3] ||  // rec1 is up of rec2
            rec1[3] <= rec2[1])    // rec1 is bottom of rec2
            return false;
        return true;
    }
};