Lienqwq @ 2022-05-21 14:40:40
#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll f[25][25][25],a,b,c;
ll w(ll a,ll b,ll 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(f[a][b][c]!=0)return w(20,20,20);
else if(a<b&&b<c) f[a][b][c]=w(a,b-1,c-1)-w(a,b-1,c);
else 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);
return f[a][b][c];
}
int main()
{
while(scanf("%lld%lld%lld",&a,&b,&c)==3)
{
memset(f,0,sizeof(f));
if(a==-1&&b==-1&&c==-1)break;
printf("w(%lld, %lld, %lld) = %lld\n",a,b,c,w(a,b,c));
}
return 0;
}by metaphysis @ 2022-05-21 14:56:00
@abablx
需要记忆化求值。
by Lienqwq @ 2022-05-21 15:12:56
@metaphysis 请问else if(f[a][b][c]!=0)return f[a][b][c];这个算记忆化吗？
by metaphysis @ 2022-05-21 15:20:46
@abablx
算记忆化，但是实现细节有问题。
by metaphysis @ 2022-05-21 15:23:14
@abablx
#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll f[32][32][32];
ll w(ll a,ll b,ll 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))
{
if(a==-1&&b==-1&&c==-1)break;
printf("w(%d, %d, %d) = %lld\n",a,b,c,w(a,b,c));
}
return 0;
}by Lienqwq @ 2022-05-21 15:26:53
@metaphysis 过了，谢谢！
by Bingxiu @ 2022-05-27 13:26:41
else if(f[a][b][c]!=0)return w(20,20,20); 你看一眼是不是这里写错了，似乎应该是f[a][b][c]