1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<cmath> 5 using namespace std; 6 #define lsn l, mid, rt << 1 7 #define rsn mid + 1, r, rt << 1 | 1 8  9 //因为只有两个矩形，所以可以不一定要用扫描线线段树的方法10 //这个简单的方法到时候可以再实现11 /*12 typedef double db;13 struct Scan{14     double l, r, h; int d;15     Scan(){}16     Scan(double l, double r, double h, int d) : l(l), r(r), h(h), d(d){}17     bool operator < (const Scan & a){18         return this->h < a.h;  //updata19     }20 }scan[100];           //updata21 double sum[100];22 double dot[100];23 int cnt[100];24 25 void push_up(int l, int r, int rt){26     if(cnt[rt]) sum[rt] = dot[r + 1] - dot[l];      //updata27     else if(l == r) sum[rt] = 0;28     else sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];29 }30 void update(int L, int R, int v, int l, int r, int rt){31     if(L <= l && R >= r){32         cnt[rt] += v;33         push_up(l, r, rt); //updata34         return;35     }36     int mid = (l + r) >> 1;37     if(L <= mid) update(L, R, v, lsn);38     if(R > mid) update(L, R, v, rsn);39     push_up(l, r, rt);40 }41 42 int main(){43     int cnt1=0, cnt2 = 0;44      double ans = 0;45      for(int i = 1; i < 3; i++){46         double x1, y1, x2, y2;47         cin >> x1 >> y1 >> x2 >> y2;48         ans += (x2 - x1) * (y2 - y1);49         scan[++cnt1] = Scan(x1, x2, y1, 1);50         scan[++cnt1] = Scan(x1, x2, y2, -1);51         dot[++cnt2] = x1; dot[++cnt2] = x2;52      }53      sort(scan + 1, scan + 1 + cnt1);54      sort(dot + 1, dot + 1 + cnt2);55      int m = 1;56      for(int i = 2; i <= cnt2; i++){57         if(dot[i] != dot[i - 1]) dot[++m] = dot[i];58      }59      double Ans = 0;60      //for(int i=1; i<=cnt1; i++) cout << scan[i].h << " ";61      //cout <<endl;62      for(int i = 1; i < cnt1; i++){63         int l = lower_bound(dot + 1, dot + 1 + m, scan[i].l) - dot;64         int r = lower_bound(dot + 1, dot + 1 + m, scan[i].r) - dot;65         //cout << l << " " << r << endl;66         if(l < r) update(l, r - 1, scan[i].d, 1, m, 1);67         //updata68         Ans += sum[1] * (scan[i + 1].h - scan[i].h);69         //cout << Ans << " " << sum[1] << " " << i <<  " " << scan[i+1].h << " " << scan[i].h << " " << scan[i + 1].h - scan[i].h << endl;70      }71     //cout << ans << " " << Ans << endl;72     printf("%.2f\n", ans - Ans);73     return 0;74 }75 */76 //这里有个坑。。。输入并不一定是先输入矩形的左下角再输入矩形的右下角，所以在判断是否有交之前我们要先sort一下，将左下角的坐标放在前面的位置77 //不得不服别人的智商。。。很巧妙啊78 double x[4], y[4];79 int main(){80     for(int  i = 0; i < 4; i += 2){81         cin >> x[i] >> y[i] >> x[i+1] >> y[i+ 1];82     }83     sort(x, x+2);84     sort(x+2, x+4);85     sort(y, y+2);86     sort(y+2, y+4);87     if(x[0] >= x[3] || x[1] <= x[2] || y[0] >= y[3] || y[1] <= y[2]){88         printf("0.00\n");89     }else{90         sort(x, x+4);91         sort(y, y+4);92         printf("%.2lf\n", (x[2] - x[1]) * (y[2] - y[1]) );93     }94     return 0;95 }