http://poj.org/problem?id=1151
http://www.cnblogs.com/kane0526/archive/2013/02/26/2934214.html这篇博客写的不错 主要是图画的不错
求面积并 离散化后 通过添加矩形的x方向边 用线段树不断更新（要求的分割开的）矩形的长和宽
1 #include <iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<cstring> 5 #define maxn 5050 6 using namespace std; 7 struct node 8 { 9 double lx,rx,y; 10 int s; 11 node(){} 12 node(double a,double b,double c,int d):lx(a),rx(b),y(c),s(d){} 13 bool operator < (const node &S) const 14 { 15 return y<S.y; 16 } 17 }mat[maxn]; 18 double que[maxn],sum[maxn]; 19 int cnt[maxn]; 20 int bin(double x,int n) 21 { 22 int s,e,m; 23 s=0;e=n; 24 while(s<=e) 25 { 26 m = (s+e)/2; 27 if(que[m]==x) 28 return m; 29 else if(que[m]>x) 30 e = m-1; 31 else 32 s = m+1; 33 } 34 return m; 35 } 36 void pushup(int l,int r,int w) 37 { 38 if(cnt[w]) 39 sum[w] = que[r+1]-que[l]; 40 else if(l==r) 41 sum[w] = 0; 42 else 43 sum[w] = sum[w<<1]+sum[w<<1|1]; 44 } 45 void update(int a,int b,int d,int l,int r,int w) 46 { 47 if(a<=l&&b>=r) 48 { 49 cnt[w]+=d; 50 pushup(l,r,w); 51 return ; 52 } 53 int m = (l+r)>>1; 54 if(a<=m) 55 update(a,b,d,l,m,w<<1); 56 if(b>m) 57 update(a,b,d,m+1,r,w<<1|1); 58 pushup(l,r,w); 59 } 60 int main() 61 { 62 int i,k,n,cas=1; 63 double a,b,c,d; 64 while(cin>>n) 65 { 66 if(n==0) break; 67 int num = 0; 68 for(i = 1; i <= n ; i++) 69 { 70 cin>>a>>b>>c>>d; 71 que[num] = a; 72 mat[num++]=node(a,c,b,1); 73 que[num] = c; 74 mat[num++] = node(a,c,d,-1); 75 } 76 sort(que,que+num); 77 sort(mat,mat+num); 78 k = 1; 79 for(i = 1 ; i < num ; i++) 80 { 81 if(que[i]!=que[i-1]) 82 que[k++] = que[i]; 83 } 84 double ans=0; 85 memset(cnt,0,sizeof(cnt)); 86 memset(sum,0,sizeof(sum)); 87 for(i = 0 ; i < num-1 ; i++) 88 { 89 int l = bin(mat[i].lx,k-1); 90 int r = bin(mat[i].rx,k-1)-1; 91 if(l<=r) 92 update(l,r,mat[i].s,0,k-1,1); 93 ans+=sum[1]*(mat[i+1].y-mat[i].y); 94 } 95 printf("Test case #%d Total explored area: %.2f ",cas++,ans); 96 } 97 return 0; 98 }