题目链接：http://hihocoder.com/problemset/problem/1249
题目大意：有一个大正方形里面有好多不重叠的小矩形，怎么找出一条竖线分割这个正方形，使得两边的矩形面积尽量相等并且正方形左边的面积比右边大
思路：做两次二分就好了
1 #include <stdio.h> 2 #include <iostream> 3 #include <algorithm> 4 using namespace std; 5 #define xx first 6 #define yy second 7 struct node{ 8 int len,wid; 9 long long sum; 10 pair<int,int> p1; 11 pair<int,int> p2; 12 void cal(){ 13 p2.xx=p1.xx+len; 14 p2.yy=p1.yy-wid; 15 sum=(long long)len*wid; 16 } 17 }; 18 bool cmp(const node&a,const node&b){ 19 return a.p1.xx<b.p1.xx; 20 } 21 const int maxn=1e4+10; 22 node a[maxn]; 23 int n,r; 24 long long check(int x){ 25 long long tmp=0; 26 for(int i=1;i<=n;i++){ 27 tmp+=((long long )a[i].wid*max(min(a[i].len,x-a[i].p1.xx),0)); 28 } 29 return tmp; 30 } 31 int binary_search(int R,long long sum){ 32 int l=-1,r=R+1; 33 int mid; 34 while(r-l>1){ 35 mid=(l+r)>>1; 36 long long tmp=check(mid); 37 if(tmp>=sum-tmp){ 38 r=mid; 39 } 40 else l=mid; 41 } 42 long long ans=check(r); 43 l=-1,r=R+1; 44 while(r-l>1){ 45 mid=(l+r)>>1; 46 long long tmp=check(mid); 47 if(tmp>ans) r=mid; 48 else l=mid; 49 } 50 return l; 51 } 52 int main(){ 53 int T; 54 //freopen("C:\Users\acm\Desktop\2015Beijing\in.txt","r",stdin); 55 scanf("%d",&T); 56 while(T--){ 57 scanf("%d",&r); 58 scanf("%d",&n); 59 long long sum=0; 60 for(int i=1;i<=n;i++){ 61 int x,y,len,wid; 62 scanf("%d %d %d %d",&x,&y,&len,&wid); 63 sum+=((long long)len*wid); 64 a[i].len=len,a[i].wid=wid,a[i].p1=make_pair(x,y),a[i].cal(); 65 } 66 sort(a+1,a+1+n,cmp); 67 printf("%d ",binary_search(r,sum)); 68 } 69 return 0; 70 }