思路：
先二分下界，再二分上届。
1 #include <bits/stdc++.h> 2 3 using namespace std; 4 5 #define MP make_pair 6 #define PB push_back 7 typedef long long LL; 8 typedef pair<int,int> PII; 9 const double eps=1e-8; 10 const double pi=acos(-1.0); 11 const int K=1e6+7; 12 const int mod=1e9+7; 13 14 struct node 15 { 16 int x,y,w,h; 17 node(){} 18 node(int a,int b,int c,int d){x=a,y=b,w=c,h=d;} 19 }rc[K]; 20 21 LL sum,ls; 22 LL check(int x,int n) 23 { 24 LL ret=0; 25 for(int i=1;i<=n;i++) 26 if(rc[i].x+rc[i].w<=x) 27 ret+=rc[i].w*1LL*rc[i].h; 28 else if(rc[i].x<=x) 29 ret+=1LL*(x-rc[i].x)*rc[i].h; 30 return ret; 31 } 32 int main(void) 33 { 34 //freopen("in.acm","r",stdin); 35 int t;cin>>t; 36 while(t--) 37 { 38 int R,l,r,n,ll,rr; 39 sum=0,ls=1e15; 40 scanf("%d%d",&R,&n); 41 for(int i=1;i<=n;i++) 42 scanf("%d%d%d%d",&rc[i].x,&rc[i].y,&rc[i].w,&rc[i].h),sum+=1LL*rc[i].w*rc[i].h; 43 l=0,r=R; 44 while(l<=r) 45 { 46 int mid=l+r>>1; 47 LL ret=check(mid,n); 48 if(ret>=sum-ret) 49 ll=mid,r=mid-1; 50 else 51 l=mid+1; 52 } 53 ls=2LL*check(ll,n)-sum; 54 l=ll,r=R; 55 while(l<=r) 56 { 57 int mid=l+r>>1; 58 LL ret=check(mid,n); 59 if(2LL*ret-sum<=ls) 60 rr=mid,l=mid+1; 61 else 62 r=mid-1; 63 } 64 printf("%d ",rr); 65 } 66 return 0; 67 }