uva 11538 计数原理

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <climits>
 5 using namespace std;
 6 
 7 typedef long long ll;
 8 
 9 ll a( ll n, ll m )
10 {
11     return n * m * ( m - 1 );
12 }
13 
14 ll b( ll n, ll m )
15 {
16     return a( m, n );
17 }
18 
19 ll d( ll n, ll m )
20 {
21     return n * ( n - 1 ) * ( n - 2 ) / 3 * 4 + 2 * ( m - n + 1 ) * n * ( n - 1 );
22 }
23 
24 int main ()
25 {
26     ll n, m;
27     while ( cin >> n >> m )
28     {
29         if ( n == 0 && m == 0 ) break;
30         if ( n > m ) swap( n, m );
31         cout << a( n, m ) + b( n, m ) + d( n, m ) << endl;
32     }
33     return 0;
34 }