[LeetCode] Rectangle Overlap

Given two rectangles, find if the given two rectangles overlap or not.

Example

Example 1:

Input : l1 = [0, 8], r1 = [8, 0], l2 = [6, 6], r2 = [10, 0]
Output : true

Example 2:

Input : l1 = [0, 8], r1 = [8, 0], l2 = [9, 6], r2 = [10, 0]
Output : false

Notice

l1: Top Left coordinate of first rectangle.
r1: Bottom Right coordinate of first rectangle.
l2: Top Left coordinate of second rectangle.
r2: Bottom Right coordinate of second rectangle.

l1 != r2 and l2 != r2

分析：一开始想的是让其中一个rectangle的某个顶点放在另一个rectangle里。这里忽略了一个下图所示case。所以这题的关键点是求重叠部分，然后看所求出的重叠部分是否valid。

 

⚠️注意edge case！！！

public class Solution {
    /**
     * @param l1: top-left coordinate of first rectangle
     * @param r1: bottom-right coordinate of first rectangle
     * @param l2: top-left coordinate of second rectangle
     * @param r2: bottom-right coordinate of second rectangle
     * @return: true if they are overlap or false
     */
    public boolean doOverlap(Point l1, Point r1, Point l2, Point r2) {
        
        int x1 = Math.max(l1.x, l2.x);
        int x2 = Math.min(r1.x, r2.x);
        
        int y1 = Math.max(r1.y, r2.y);
        int y2 = Math.min(l1.y, l2.y);
        
        if (x2 >= x1 && y2 >= y1) {
            return true;
        } else {
            return false;
        }
    }

}