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;
}