luogu P2015 二叉苹果树

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 110

struct EDGE{
  int nxt,to,weight;
}edge[maxn * 2];//因为忘了开二倍所以emmm

int head[maxn],cnt;
int dp[maxn][maxn];
int n,q;

void add(int x,int y,int w){
  edge[++cnt].nxt = head[x];
  edge[cnt].to = y;
  head[x] = cnt;
  edge[cnt].weight = w;
}

int treedp(int u,int fa){
  int num = 0;
  for(int i = head[u];i;i = edge[i].nxt){
    int v = edge[i].to;
    if(v != fa){//存的双向所以防止死循环
      num += treedp(v,u) + 1;//return一个值，子树的边数，再加上相连的一条
      for(int j = min(num,q);j > 0;j--)
    for(int k = min(num,j);k >= 0;k--)
      dp[u][j] = max(dp[u][j],dp[u][j - k - 1] + dp[v][k] + edge[i].weight);
    }
  }
  return num;
}

int main(){
  scanf("%d%d",&n,&q);
  for(int i = 1;i < n;i++){
    int x,y,w;
    scanf("%d%d%d",&x,&y,&w);
    add(x,y,w);
    add(y,x,w);
  }
  treedp(1,0);
  printf("%d",dp[1][q]);
  return 0;
}