UVa 免费糖果(记忆化搜索)

#include<iostream>
#include<cstring>
#define fo(i,a,b) for(int i=a;i<=b;i++)
#define fod(i,a,b) for(int i=a;i>=b;i--)
using namespace std;
const int N=40+5,M=20+5;
int dp

,top[5],pile[5]
,
n;
bool Hash
;

void Init() {
fo(i,0,n-1) fo(j,0,3) scanf("%d",&pile[j][i]);
memset(dp,-1,sizeof(dp));
memset(top,0,sizeof(top));
memset(Hash,0,sizeof(Hash));
}

int dfs(int count, bool Hash[]) {
if (dp[top[0]][top[1]][top[2]][top[3]] != -1)
return dp[top[0]][top[1]][top[2]][top[3]];

if (count == 5)
return dp[top[0]][top[1]][top[2]][top[3]] = 0;

int ans = 0;
for (int i = 0; i < 4; i++) {
if (top[i] == n) continue;
int color = pile[i][top[i]];
top[i] += 1;
if (Hash[color]) {
Hash[color] = false;
ans = max(ans, dfs(count-1, Hash) + 1);
Hash[color] = true;
} else {
Hash[color] = true;
ans = max(ans, dfs(count+1, Hash));
Hash[color] = false;
}
top[i] -= 1;
}
return dp[top[0]][top[1]][top[2]][top[3]] = ans;
}

int main() {
while(scanf("%d",&n)&&n) {
Init();
printf("%d\n",dfs(0,Hash));
}
return 0;
}