HDU5100

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <cctype>
 5 #include <cmath>
 6 #include <ctime>
 7 #include <string>
 8 #include <map>
 9 #include <stack>
10 #include <set>
11 #include <vector>
12 #include <algorithm>
13 #include <iostream>
14 using namespace std;
15 typedef long long ll;
16 #define PI acos( -1.0 )
17 const double E = 1e-8;
18 int n, m;
19 
20 int main()
21 {
22     int T;
23     scanf( "%d", &T );
24     while( T-- )
25     {
26         scanf( "%d%d", &n, &m );
27         if( m > n )
28         {
29             puts( "0" );
30             continue;
31         }
32         int t = n % m;
33         if( t <= m / 2 )
34             printf( "%d\n", n*n - t*t );
35         else
36             printf( "%d\n", n*n - ( m-t )*( m-t ) );
37     }
38     return 0;
39 }