URAL1018 Binary Apple Tree(树dp)

组队赛的时候的一道题，那个时候想了一下感觉dp不怎么好写呀，现在写了出来，交上去过了，但是我觉得我还是应该WA的呀，因为总感觉dp的不对。

#pragma warning(disable:4996)

#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstring>

#include<string>

#include<vector>

#define maxn 150

using namespace std;



struct Edge

{

	int v, w;

	Edge(int vi, int wi) :v(vi), w(wi){}

	Edge(){}

};



vector<Edge> G[maxn];

int n, q;

int dp[maxn][maxn];

int tmp[maxn];



void dfs(int u, int fa)

{

	for (int i = 0; i < G[u].size(); i++){

		int v = G[u][i].v, w = G[u][i].w;

		if (v == fa) continue;

		dfs(v, u);

		memcpy(tmp, dp[u], sizeof(dp[u]));

		for (int k = q; k >= 0; k--){

			for (int j = k - 1; j >= 0; j--){

				dp[u][k] = max(dp[u][k], dp[v][j] + tmp[k-1- j] + w);

			}

		}

	}

}



int main()

{

	while (cin >> n >> q)

	{

		for (int i = 0; i <= n; i++) G[i].clear();

		int ui, vi, wi;

		for (int i = 0; i < n - 1; i++){

			scanf("%d%d%d", &ui, &vi, &wi);

			G[ui].push_back(Edge(vi, wi));

			G[vi].push_back(Edge(ui, wi));

		}

		memset(dp, 0, sizeof(dp));

		dfs(1, -1);

		cout << dp[1][q] << endl;

	}

	return 0;

}