[LeetCode-Algorithms-223] "Rectangle Area" (2018.1.1-WEEK18)

题目链接：Rectangle Area

• 题目描述：
  

Find the total area covered by two rectilinear rectangles in a 2D plane.

Each rectangle is defined by its bottom left corner and top right corner as shown in the figure.

Assume that the total area is never beyond the maximum possible value of int.

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(1)思路：这题相对比较简单，用两个长方形面积之和减去重合部分面积就是总面积。但是提交时发现只能使用类似a<b来判断a、b大小，不能使用c = a - b这样的c来判断是否小于0，会溢出。

(2)代码：

class Solution {
public:
    int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
        int a1 = (C - A) * (D - B);
        int a2 = (G - E) * (H - F);

        int w1 = max(A, E);
        int w2 = min(C, G);
        int w = w2 - w1;

        int h1 = max(B, F);
        int h2 = min(D, H);
        int h = h2 -h1;
        if(h2 < h1 || w2 < w1) return (a1 + a2);
        else return (a1 + a2 - w * h);
    }
};

(3)提交结果：