NYOJ 697 The Weight of Tree

#include <iostream>
#include <cstdio>
#include <string.h>
#include <vector>
using namespace std;
bool vis[100010];
int point[100010];
vector<int> m[100010];
int maxn;
int dfs(int i)
{
vis[i]=1;
int res=point[i], term, len=m[i].size();
for (int j=0; j<len; j++)
{
if (vis[m[i][j]]==0)
{
term=dfs(m[i][j]);
if (term>0) res+=term;//如果大于0，就加上，小于0不操作
}
}
if (maxn<res) maxn=res;//更新最大值
return res;
}
int main()
{
//	freopen("in", "r", stdin);
int T, n, i, a, b;
scanf("%d", &T);
while (T--)
{
memset(vis, 0, sizeof (vis));
scanf("%d", &n);
for (i=1; i<=n; i++)
scanf("%d", &point[i]);
for (i=1; i<n; i++)
{
scanf("%d%d", &a, &b);
m[a].push_back(b);
m[b].push_back(a);
}
maxn=1<<31;
dfs(1);
printf("%d\n", maxn);
for (i=1; i<=n; i++) m[i].clear();
}
return 0;
}