90分，求助求助求助！

#include<stdio.h>
int main()
{
    int n,m,i;
    long long s;
    scanf("%d%d%lld",&n,&m,&s);
    int a[n][2],b[m][2],max=1,min=0xfffffff;
    for(i=0;i<n;i++)
    {
        scanf("%d%d",a[i],a[i]+1);
        if(max<a[i][0]) max=a[i][0];
        if(min>a[i][0]) min=a[i][0];
    } 
    for(i=0;i<m;i++) scanf("%d%d",b[i],b[i]+1);
    int r=max+2,l=min-1,mid;
    long long sum,ans=0xFFFFFFFFFFFFFFF;
    while(r>=l)
    {
        mid=(r+l)/2,sum=0;
        int pre_n[n+1],pre_v[n+1];
        pre_n[0]=pre_v[0]=0;
        for(i=1;i<=n;i++)
        {
            if(a[i-1][0]>=mid) pre_n[i]=pre_n[i-1]+1,pre_v[i]=pre_v[i-1]+a[i-1][1];
            else pre_n[i]=pre_n[i-1],pre_v[i]=pre_v[i-1]; 
        }
        for(i=0;i<m;i++) sum+=(pre_n[b[i][1]]-pre_n[b[i][0]-1])*(pre_v[b[i][1]]-pre_v[b[i][0]-1]);
        long long ans_x=sum>s?sum-s:s-sum;
        if(ans_x<ans) ans=ans_x;
        if(ans_x=0) break;
        else if(sum<s) r=mid-1;
        else if(sum>s) l=mid+1;
    }
    printf("%lld",ans);
    return 0;
}