求序列的和，杭电0j-2058

 1 #include <iostream>
 2 #include <math.h>
 3 using namespace std;
 4 int main()
 5 {
 6     __int64 m, n;
 7     while(cin >> n >> m, n||m)
 8     {
 9         __int64 a, k;
10         for(k=(int)sqrt(2*m); k>0; k--)
11         {
12             a = m/k-(k-1)/2;
13             if((2*a-1+k)*k == 2*m)
14                 cout << "[" << a << "," << k+a-1 << "]" << endl;
15         }
16     cout << endl;
17     }
18     return 0;
19 }