HDU1561 The more, The Better（树形依赖背包）

题目链接
题意：略
解法：09《浅谈几类背包问题》有详解

#include<cstdio>#include<algorithm>#include<vector>#include<cstring>#include<string>using namespace std;const int maxn=205;#define LL long long#define pb push_back#define cl(a,b) memset(a,b,sizeof(a))LL val[maxn];LL dp[maxn][maxn];int n,m;int x[maxn];void dfs(int k,int C){    if(C<=0)return ;    for(int i=1;i<=n;i++)if(x[i]==k){        for(int j=0;j<C;j++)            dp[i][j]=dp[k][j]+val[i];        dfs(i,C-1);        for(int j=1;j<=C;j++){            dp[k][j]=max(dp[k][j],dp[i][j-1]);        }    }}int main(){    while(~scanf("%d%d",&n,&m)&&(n||m)){        for(int i=1;i<=n;i++){            scanf("%d%lld",&x[i],&val[i]);        }        cl(dp,0);        dfs(0,m);        printf("%lld\n",dp[0][m]);    }    return 0;}