LeetCode Rectangle Area

原题链接在这里：https://leetcode.com/problems/rectangle-area/

思路: 方块1面积 + 方块2面积 - 重叠面积

Note:  算重叠的面积时会有overflow，并且很难发现.  Math.min(C,G) 之前必须加 cast, 

原来写(long)(Math.min(C,G) - Math.max(A,E))会报错是因为Math.min(C,G)和Math.max(A,E)都是 Integer, 所以cast之前的结 果会default成Integer, 还是会有overflow.

AC Java:

public class Solution {
    public int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
        int area1 = (C-A)*(D-B);
        int area2 = (G-E)*(H-F);
        
        int overlap;
        long width = Math.max((long)(Math.min(C,G) - (long)Math.max(A,E)),0);
        long length = Math.max((long)(Math.min(D,H) - (long)Math.max(B,F)),0);
        overlap = (int)(width*length);
        return area1 + area2 - overlap;
    }
}