> #include<iostream>
> #include<cstdio>
> using namespace std;
> 
> int w[25][25][25];
> 
> int main()
> {
> 	int i,j,k,a,b,c;
> 	cin>>a>>b>>c;
> 	for(i=0;i<=20;i++)
> 	{
> 		for(j=0;j<=20;j++)
> 		{
> 			for(k=0;k<=20;k++)
> 			{
> 				if(i==0||j==0||k==0)
> 					w[i][j][k]=1;
> 				else if(i<j&&j<k)
> 					w[i][j][k]=w[i][j][k-1]+w[i][j-1][k-1]-w[i][j-1][k];
> 				else
> 					w[i][j][k]=w[i-1][j][k]+w[i-1][j-1][k]+w[i-1][j][k-1]-w[i-1][j-1][k-1];
> 			}
> 		}
> 	}
> 	while(a!=-1||b!=-1||c!=-1)
> 	{
> 		if(a>20||b>20||c>20)
> 			printf("w(%d, %d, %d) = %d\n",a,b,c,w[20][20][20]);
> 		else if(a<=0||b<=0||c<=0)
> 			printf("w(%d, %d, %d) = 1\n",a,b,c);
> 		else
>     		printf("w(%d, %d, %d) = %d\n",a,b,c,w[a][b][c]);
> 		cin>>a>>b>>c;
> 	}
> 	return 0;
> }
溢出了