Crazy Bobo
Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 131072/65536 K (Java/Others)
Total Submission(s): 612 Accepted Submission(s): 189
Problem Description
Bobo has a tree,whose vertices are conveniently labeled by 1,2,...,n.Each node has a weight wi.
All the weights are distrinct.
A set with m nodes v1,v2,...,vm is
a Bobo Set if:
- The subgraph of his tree induced by this set is connected.
- After we sort these nodes in set by their weights in ascending order,we get u1,u2,...,um,(that
is,wui<wui+1 for
i from 1 to m-1).For any node x in
the path from ui to ui+1(excluding ui and ui+1),should
satisfy wx<wui.
Your task is to find the maximum size of Bobo Set in a given tree.
All the weights are distrinct.
A set with m nodes v1,v2,...,vm is
a Bobo Set if:
- The subgraph of his tree induced by this set is connected.
- After we sort these nodes in set by their weights in ascending order,we get u1,u2,...,um,(that
is,wui<wui+1 for
i from 1 to m-1).For any node x in
the path from ui to ui+1(excluding ui and ui+1),should
satisfy wx<wui.
Your task is to find the maximum size of Bobo Set in a given tree.
Input
The input consists of several tests. For each tests:
The first line contains a integer n (1≤n≤500000).
Then following a line contains n integers w1,w2,...,wn (1≤wi≤109,all
the wi is
distrinct).Each of the following n-1 lines contain 2 integers ai and bi,denoting
an edge between vertices ai and bi (1≤ai,bi≤n).
The sum of n is not bigger than 800000.
The first line contains a integer n (1≤n≤500000).
Then following a line contains n integers w1,w2,...,wn (1≤wi≤109,all
the wi is
distrinct).Each of the following n-1 lines contain 2 integers ai and bi,denoting
an edge between vertices ai and bi (1≤ai,bi≤n).
The sum of n is not bigger than 800000.
Output
For each test output one line contains a integer,denoting the maximum size of Bobo Set.
Sample Input
7
3 30 350 100 200 300 400
1 2
2 3
3 4
4 5
5 6
6 7
Sample Output
5
Source
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5324 5323 5322 5321/* 參考此人博客 :http://www.mamicode.com/info-detail-948802.html
记得用c++交 */ #pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<string>
#include<iostream>
#include<queue>
#include<cmath>
#include<map>
using namespace std; #define N 800005 vector<int>g[N];
int n;
int ans[N];
int a[N]; int dfs(int u)
{
if(ans[u]) return ans[u];
ans[u]=1;
for(int i=0;i<g[u].size();i++)
{
int to=g[u][i];
ans[u]+=dfs(to);
}
return ans[u];
} int main()
{
int i,j;
while(~scanf("%d",&n))
{
for(i=1;i<=n;i++)
scanf("%d",&a[i]);
for(i=1;i<=n;i++)
g[i].clear();
memset(ans,0,sizeof(ans));
int u,v;
i=n-1;
while(i--)
{
scanf("%d%d",&u,&v);
if(a[u]<a[v]) g[u].push_back(v);
else g[v].push_back(u);
}
int temp=0;
for(i=1;i<=n;i++)
{
temp=max(temp,dfs(i));
}
printf("%d\n",temp);
}
return 0;
}