POJ 1579

#include <iostream>
#include <cstdio>
using namespace std;
const int maxn = 55;
int f[maxn][maxn][maxn];

int w(int a, int b, int c) {
    if(a <= 0 || b <= 0 || c <= 0) {
        return 1;
    }
    if(a > 20 || b > 20 || c > 20) {
        return  w(20, 20, 20);
    }
    if(f[a][b][c]) {
        return f[a][b][c];
    }
    if(a < b && b < c) {
        return  f[a][b][c] = w(a, b, c-1) + w(a, b-1, c-1) - w(a, b-1, c);
    }
    return f[a][b][c] = 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()
{
    int a, b, c;
    while(scanf("%d%d%d", &a, &b, &c) != EOF){
        if(a == -1 && b== -1 && c == -1) {
            return 0;
        }
        int res = w(a, b, c);
        printf("w(%d, %d, %d) = %d\n", a, b, c, res);
    }
    return 0;
}
//多多练习，不要眼高手低。