AcWing每日一题（提高组）--聪明的质监员

https://www.acwing.com/problem/content/501/

 

 

#include<iostream>
using namespace std;
const int N=200010;
typedef long long LL;
int v[N],w[N];
int L[N],R[N];
int n,m;
LL S;
LL sum[N],cnt[N];
LL get_Y(int W){
    for(int i=1;i<=n;i++){
        if(w[i]>=W){
            sum[i]=sum[i-1]+v[i];
            cnt[i]=cnt[i-1]+1;
        }else{
            sum[i]=sum[i-1];
            cnt[i]=cnt[i-1];
        }
    }
    LL res=0;
    for(int i=1;i<=m;i++){
        res += (sum[R[i]] - sum[L[i] - 1]) * (cnt[R[i]] - cnt[L[i] - 1]);
    }
    return res;
}
int main(void){
    cin>>n>>m>>S;
    for(int i=1;i<=n;i++){
        cin>>w[i]>>v[i];
    }
    for(int i=1;i<=m;i++){
        cin>>L[i]>>R[i];
    }
    int l=0,r=1e6+1;
    while(l<r){
        int mid=l+r+1>>1;
        if(get_Y(mid)>=S){
            l=mid;
        }else{
            r=mid-1;
        }
    }
    cout<<min(get_Y(r)-S,S-get_Y(r+1));
    return 0;
}