状压dp:luogu P2704 [NOI2001]炮兵阵地

https://www.luogu.org/problemnew/show/P2704

知识点：1.滚动数组：取模实现

2.位运算优先级最低

顾是if(!(a&b))而不是if(!a&b)

code:

#include <bits/stdc++.h>
#define N 101
#define M 10
using namespace std;
int n,m;
int tot = ;
int dp[][][],mp[N],state[];
int val[];
int check(int k)
{
     if(((k&(k<<))==)&&((k&(k<<))==)&&((k&(k>>))==)&&((k&(k>>))==))return ;
     else return ;
}
int get(int k)
{
    int ans = ;
    for(int i = ;i < m;i++)
    {
        if(k&( << i))ans++;
    }
    return ans;
}
char ch[N];
int main()
{
    scanf("%d%d",&n,&m);
    for(int i = ;i <= n;i++)
    {
        scanf("%s",ch);
        for(int j = ;j < m;j++)
        {
            if(ch[j] == 'H')
            {
                mp[i] = mp[i]|( << j);
            }
        }
    }
    for(int i = ;i <= ( << m) - ;i++)
    {
        if(check(i))
        {
            state[++tot] = i;
            val[tot] = get(i);
            dp[][][tot] = val[tot];
        }
    }
    for(int i = ;i <= tot;i++)
    {
        for(int j = ;j <= tot;j++)
        {
            if((state[i]&state[j]) == &&(state[i]&mp[]) == )
            dp[][j][i] = max(dp[][j][i],dp[][][j] + val[i]);
        }
    }
    for(int i = ;i <= n;i++)
    {
        for(int j = ;j <= tot;j++)
        if((state[j]&mp[i]) == )
        for(int k = ;k <= tot;k++)
        if((state[k]&mp[i - ]) == )
        for(int p = ;p <= tot;p++)
        if((state[p]&mp[i - ]) == )
        if((state[p]&state[k]) ==  && (state[k]&state[j]) ==  && (state[p]&state[j]) == )
        dp[i % ][k][j] = max(dp[i % ][k][j],dp[(i - ) % ][p][k] + val[j]);
    }
    int ans = -;
    for(int i = ;i <= tot;i++)
    for(int j = ;j <= tot;j++)
    ans = max(dp[n % ][j][i],ans);
    printf("%d",ans);
    return ;
}