delete pics to save space

p.HDOJ2196.cpp

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+//http://acm.hdu.edu.cn/showproblem.php?pid=2196
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+#include<vector>
+using namespace std;
+const int maxn=10005;
+int n,d[maxn],f[maxn],val[maxn][2];
+vector<int> G[maxn],E[maxn];
+void dfs1(int u)
+{
+	for(int i=0;i<G[u].size();i++)
+	{
+		dfs1(G[u][i]);
+		d[u]=max(d[u],E[u][i]+d[G[u][i]]);
+	}
+}
+void dfs2(int u,int fa,int w)
+{
+	f[u]=w+f[fa];
+	if(d[u]+w==val[fa][0]) f[u]=max(f[u],w+val[fa][1]);
+	else f[u]=max(f[u],w+val[fa][0]);
+	for(int i=0;i<G[u].size();i++)
+	{
+		int t=d[G[u][i]]+E[u][i];
+		if(t>val[u][0]) { val[u][1]=val[u][0]; val[u][0]=t; }
+		else val[u][1]=max(val[u][1],t);
+	}
+	for(int i=0;i<G[u].size();i++) dfs2(G[u][i],u,E[u][i]);
+}
+int main()
+{
+	#ifdef local
+	freopen("pro.in","r",stdin);
+	#endif
+	while(scanf("%d",&n)==1)
+	{
+		for(int i=1;i<=n;i++) { G[i].clear(); E[i].clear(); }
+		memset(d,0,sizeof(d));
+		memset(f,0,sizeof(f));
+		memset(val,0,sizeof(val));
+		for(int i=2;i<=n;i++)
+		{
+			int v,w; scanf("%d%d",&v,&w);
+			// G[i].push_back(v);
+			G[v].push_back(i);
+			E[v].push_back(w);
+		}
+		dfs1(1);
+		dfs2(1,0,0);
+		for(int i=1;i<=n;i++) printf("%d\n",max(f[i],d[i]));
+	}
+	return 0;
+}