递归算法，全部TLE

#include <iostream>
#include <stdio.h>
using namespace std ;
long long w ( long long a , long long b , long long c ) {
	if ( a <= 0 || b <= 0 || c <= 0 ) return 1 ;
	else if ( a > 20 || b > 20 || c > 20 ) return w ( 20 , 20 , 20 ) ;
	else if ( a < b && b < c ) return w ( a , b , c-1 ) + w ( a , b-1 , c-1 ) - w ( a , b-1 , c ) ;
	else return w ( a - 1 , b , c ) + w ( a-1 , b-1 , c ) + w ( a-1 , b , c-1 ) - w ( a-1 , b-1 , c-1 ) ;
}
int main () {
	long long a , b , c ;
	while ( cin >> a >> b >> c ) {
		if ( a == -1 && b == -1 && c == -1 ) break ;
		printf ( "w(%lld, %lld, %lld) = %lld" , a , b , c , w(a,b,c) ) ;
	}
	return 0 ;
}