《leetCode》：Rectangle Area

题目

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.

Rectangle Area

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

思路

此题比较简单，当两个矩形有交集时，则结果就是两个矩形的面积减去两个矩形的交集。如果两个矩形没有交集，则就是两个矩形的面积之和。 判断有无交集只需要判断四种情况（在上面、下面、左边、右边；其中包括了在左上方呀右上方呀左下方呀右下方）即可。

int max(int a,int b){
    return a>b?a:b;
}
int min(int a,int b){
    return a<b?a:b;
}
int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
    if(C<A||D<B||G<E||H<F){//矩形有效性检查 
        return ;
    } 
    int twoRectArea=(C-A)*(D-B)+(G-E)*(H-F);
    int x0=max(A,E);
    int y0=max(B,F);
    int x1=min(C,G);
    int y1=min(D,H);
    int intersectArea=(x1-x0)*(y1-y0);  
    if(C<=E||D<=F||G<=A||H<=B){//没有交集 
        return  twoRectArea;
    }   
    else{
        return twoRectArea-intersectArea; 
    }

}