洛谷1314 聪明的质检员 二分

题目有点长，就直接放链接了 https://www.luogu.org/problem/show?pid=1314

直接二分W值 处理前缀和和数量就可以了

注意要开long long

#include<bits/stdc++.h>
using namespace std;
#define maxn 200005
#define ll long long
int n,m;
ll S;
int w[maxn],v[maxn],l[maxn],r[maxn];
ll sum[maxn],cnt[maxn];
inline int read(){
    int x=0,f=1;char ch=getchar();
    while(ch>'9'||ch<'0'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
ll judge(int W){
    memset(sum,0,sizeof sum);
    memset(cnt,0,sizeof cnt);
    for(int i=1;i<=n;i++){
        sum[i]+=sum[i-1];
        cnt[i]+=cnt[i-1];
        if(w[i]>=W){
            sum[i]+=v[i];
            cnt[i]++;
        }
    }
    ll tmp=0;
    for(int i=1;i<=m;i++){
        tmp+=(cnt[r[i]]-cnt[l[i]-1])*(sum[r[i]]-sum[l[i]-1]);
    }
    return tmp;
}
int main(){
    scanf("%d%d%lld",&n,&m,&S);
    int mx=0;
    for(int i=1;i<=n;i++){
        scanf("%d%d",&w[i],&v[i]);
        mx=max(w[i],mx);
    }
    for(int i=1;i<=m;i++){
        scanf("%d%d",&l[i],&r[i]);
    }
    int l=0,r=mx+1;
    ll ans=(1LL<<60);
    while(l<=r){
        int mid=(l+r)>>1;
        ll t=judge(mid);
        ans=min(ans,abs(S-t));
        if(t<S)r=mid-1;//注意二分的取值 
        else l=mid+1;
    }
    printf("%lld",ans);
    return 0;
}