rt 本地，在线ide都可以运行，o2开不开都RE

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