洛谷 P3112 后卫马克 —— 状压DP

题目：https://www.luogu.org/problemnew/show/P3112

状压DP...转移不错。

代码如下：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
ll const maxn=(1<<20),inf=1e18;
ll n,H,h[25],w[25],s[25],f[maxn],mx,ans=-inf;
int main()
{
    scanf("%lld%lld",&n,&H); mx=(1<<n)-1;
    for(int i=1;i<=n;i++)scanf("%lld%lld%lld",&h[i],&w[i],&s[i]);
    f[0]=inf;//下面取min 
    for(int i=1;i<=mx;i++)
    {
        ll tmp=0; f[i]=-inf;
        for(int j=1;j<=n;j++)
            if((1<<(j-1))&i)
            {    
                tmp+=h[j];
                f[i]=max(f[i],min(f[i^(1<<(j-1))]-w[j],s[j]));
            }
        if(tmp>=H&&f[i]>0)ans=max(ans,f[i]);
    }
    if(ans<0)printf("Mark is too tall\n");
    else printf("%lld\n",ans);
    return 0;
}