有佬可以帮忙看看吗,后面三个点WA

#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main(){
    int t;
    int n=1000000;
    vector<long> prearr(n);
    prearr[0]=0;
    for(int i=1;i<n;i++){
        ll loc = (i*(i+1))/2LL;
        prearr[i]=prearr[i-1]+loc;
    }
    cin>>t;
    double l,r;
    ll ans=0;
    while(t--){
        ans=0;
        cin>>l>>r;
        //right bound
        ll rlen = (sqrt(8*r+1)-1)/2LL;
        ans+=prearr[rlen];
        ll x=r-rlen*(rlen+1)/2;
        ans+=x*(x+1)/2;
        //left bound;
        l--;
        ll llen = (sqrt(8*l+1)-1)/2LL;
        ans-=prearr[llen];
        x=l-llen*(llen+1)/2;
        ans-=x*(x+1)/2;
        cout<<ans<<endl;;
    }
    return 0;
}