我高高兴兴花了3个小时打着题，然后WA地一声哭了出来：

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    int T;
    cin>>T;
    for (int i=1;i<=T;i++)
    {
    	int l,r;
    	cin>>l>>r;
    	int sum1=0,num1;
    	for (int i=1;sum1<=l;i++)
    	{
    		sum1+=i;
    		num1=i;
		}
		int sum2=sum1,num2;
		for(int i=num1+1;sum2<=r;i++)
		{
			sum2+=i;
			num2=i;
		}
		int suml=num1*(num1+1)*(2*num1+1)/6;
		int sumr=num2*(num2+1)*(2*num2+1)/6;
		int sum=sumr-suml-(l-sum1)*(num1+1)+(r-sum2)*(num2+1);
		cout<<sum<<endl;
	}
    return 0;
}