POJ 2590

 #include<iostream>
 #include<algorithm>
 #define MAXN 1000000
 using namespace std;

 unsigned a[MAXN];

 int main()
 {
     //freopen("acm.acm","r",stdin);
     int i;
     int num = ;
     int time = ;
     int x;
     int y;
     a[] = ;
     for(i = ; i < MAXN; ++ i)
     {
         a[i] = a[i-] + num;
         ++ time;
         if(time == )
         {
             ++ num;
             time = ;
         }
     }
     cin>>num;
     while(num --)
     {
         cin>>x>>y;
         cout<<lower_bound(a,a+MAXN,abs(y-x))-a<<endl;
     }
 }