P1314 [NOIP 2011 提高组] 聪明的质监员

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#include<bits/stdc++.h>
using namespace std;typedef long long LL;
const int N=2e5+10;
int n,m;
LL s;
int w[N],v[N];
int l[N],r[N];
LL s1[N],s2[N];LL check(int x)
{for(int i=1;i<=n;i++){if(w[i]>=x){s1[i]=s1[i-1]+1;s2[i]=s2[i-1]+v[i];}else{s1[i]=s1[i-1];s2[i]=s2[i-1];}}LL Y=0;for(int i=1;i<=m;i++){LL cnt=s1[r[i]]-s1[l[i]-1];LL sum=s2[r[i]]-s2[l[i]-1];Y+=cnt*sum;}return Y;
}int main()
{ios::sync_with_stdio(0),cin.tie(0);cin>>n>>m>>s;int max_w=0;for(int i=1;i<=n;i++){cin>>w[i]>>v[i];max_w=max(w[i],max_w);}for(int i=1;i<=m;i++){cin>>l[i]>>r[i];}int L=0,R=max_w+2;LL ans=1e18;while(L<=R){int mid=L+(R-L)/2;LL Y=check(mid);if(ans>abs(Y-s)){ans=abs(Y-s);}if(Y-s>0){L=mid+1;}else{R=mid-1;}}cout<<ans<<endl;return 0;
}