luoguP1314 聪明的质监员 题解(NOIP2011)

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<iomanip>
#include<ctime>
#include<queue>
#include<stack>
#define rg register
#define lst long long
#define N 200050
#define Inf 2147483647
using namespace std;

int n,m,mx=-1,mn=Inf;
lst res,s,ss;
lst ans=999999999999999999;
int w[N],v[N],l[N],r[N];
lst tot[N],num[N];

inline lst read()
{
    rg lst s=0,m=1;rg char ch=getchar();
    while(ch!=‘-‘&&(ch<‘0‘||ch>‘9‘))ch=getchar();
    if(ch==‘-‘)m=-1,ch=getchar();
    while(ch>=‘0‘&&ch<=‘9‘)s=(s<<3)+(s<<1)+ch-‘0‘,ch=getchar();
    return s*m;
}

inline lst a_b_s(rg lst t){return t>=0?t:-t;}
inline bool check(rg int lim)
{
    res=0,ss=0;
    memset(tot,0,sizeof(tot));
    memset(num,0,sizeof(num));
    for(rg int i=1;i<=n;++i)
    {
        num[i]=num[i-1],tot[i]=tot[i-1];
        if(w[i]>=lim)num[i]++,tot[i]+=v[i];
    }
    for(rg int i=1;i<=m;++i)
        ss+=(num[r[i]]-num[l[i]-1])*(tot[r[i]]-tot[l[i]-1]);
    res=a_b_s(ss-s);
    if(ss>s)return 1;
    else return 0;
}

int main()
{
    n=read(),m=read(),s=read();
    for(rg int i=1;i<=n;++i)
    {
        w[i]=read(),v[i]=read();
        mx=max(mx,w[i]),mn=min(mn,w[i]);
    }
    for(rg int i=1;i<=m;++i)
        l[i]=read(),r[i]=read();
    rg int le=mn-1,ri=mx+2;
    while(le<=ri)
    {
        rg int mid=(le+ri)>>1;
        if(check(mid))le=mid+1;
        else ri=mid-1;
        ans=min(ans,res);
    }
    cout<<ans<<endl;
    return 0;
}