测试点数据能过但是都wal呜呜呜

#include<bits/stdc++.h>
using namespace std;
#define ull long long
ull nb[30][30][30];
int w(ull a,ull b,ull c){
    if(a<=0||b<=0||c<=0)
        return 1;
    else if(nb[a][b][c]!=0)return nb[a][b][c]; 
    else if(a>20||b>20||c>20)
        nb[a][b][c]=w(20,20,20);
    else if(a<b&&b<c) nb[a][b][c]=w(a,b,c-1)+w(a,b-1,c-1)-w(a,b-1,c);
    else nb[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);
    return nb[a][b][c];
} 
int main(){
    ull a=0,b=0,c=0,ans;
    while(scanf("%lld%lld%lld",&a,&b,&c)==3){
        memset(nb,0,sizeof(nb));
        if(a==-1&&b==-1&&c==-1)break;
        if(a>20)a=21;if(b>20)b=21;if(c>20)c=21;
        ans=w(a,b,c);
        printf("w(%lld, %lld, %lld) = %lld\n",a,b,c,ans);
    }
    return 0;
}