EZOJ #374学习

分析

二分天数

暴力判断即可

代码

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,m,a[],b[],c[],d[];
inline bool ck(int mid){
    int x=mid,i,j,k;
    for(i=;i<=n;i++)d[i]=c[i];
    for(i=;i<=n;i++)d[i]=max(0ll,d[i]-x*b[i]);
    for(i=;i<=n;i++)
      if(d[i]){
          x-=((d[i]-)/a[i]+);
          if(x<)break;
      }
    if(x>=)return ;
    return ;
}
signed main(){
    int i,j,k;
    scanf("%d",&n);
    for(i=;i<=n;i++)scanf("%d%d%d",&c[i],&b[i],&a[i]),m=max(m,(c[i]-)/b[i]+);
    int le=,ri=m;
    while(ri-le>){
      int mid=(le+ri)>>;
      if(ck(mid))ri=mid;
        else le=mid;
    }
    printf("%d\n",ri);
    return ;
}