Submission #4073980

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
int dp[110000],n,m;
vector <int> edge[110000];
int rec(int cur)
{
	if(dp[cur]>=0)
		return dp[cur];
	if(edge[cur].size()==0)
		return dp[cur]=0;
	for(int i=0;i<edge[cur].size();i++)
	{
		int to=edge[cur][i];
		dp[cur]=max(dp[cur],rec(to)+1);
	}
	return dp[cur];
}
int ans;
int main()
{
	cin>>n>>m;
	for(int i=0;i<m;i++)
	{
		int x,y;
		cin>>x>>y;
		edge[x].push_back(y);
	}
	fill(dp,dp+n+1,-1);
	for(int i=1;i<=n;i++)
	{
		rec(i);
		ans=max(ans,dp[i]);
	}
	cout<<ans<<"\n";
	return 0;
}

Submission Info

Judge Result