看了题解都没AC,我大概的确是废了

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> PII;
const int N = 2e5+10;
int v[N],w[N];
PII inv[N];
long long st[N],sw[N];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    long long n,m,s;
    cin>>n>>m>>s;
    int r = 0;
    for(int i = 1; i <= n; i ++)
    {
        cin>>v[i]>>w[i];
        r = max(r,w[i]);
    }
    for(int i = 1; i <= m; i ++)
        cin>>inv[i].first>>inv[i].second;
    int l = 0;
    long long ans = 0x3f3f3f3f3f3f3f3f;
    while(l < r)
    {
        int mid = l + r >> 1;
        for(int i = 1; i <= n; i ++)
        {
            if(v[i] >= mid)
            {
                st[i] = st[i - 1] + 1;
                sw[i] = sw[i - 1] + w[i];
            }else st[i] = st[i - 1], sw[i] = sw[i - 1];
        }
        long long val = 0,nums = 0;
        long long sum = 0;
        for(int i = 1; i <= m; i ++)
        {
            nums = st[inv[i].second] - st[inv[i].first - 1];
            val = sw[inv[i].second] - sw[inv[i].first - 1];
            sum += nums*val;
        }
        ans = min(ans,abs(sum-s));
        if(s-sum > 0)r = mid;
        else l = mid + 1;
    }
    cout << ans << endl;
}