Submission #827935

#	Time	Username	Problem	Language	Result	Execution time	Memory
827935		MohamedAhmed04	Graph (BOI20_graph)	C++14	100 / 100	108 ms	23236 KiB

Graph

#include <bits/stdc++.h>

using namespace std ;

const int MAX = 1e5 + 10 ;

int arr[MAX] ;
int n , m ;

vector< vector< pair<int , int> > >adj(MAX) ;

int vis[MAX] ;
int a[MAX] , b[MAX] ;

int known = -1 ;
bool flag = true ;

int ans[MAX] ;

vector<int>v ;

void dfs(int node)
{
	vis[node] = 1 ;
	v.push_back(a[node] * (-1 * b[node])) ;
	for(auto &childd : adj[node])
	{
		int child = childd.first , w = childd.second ;
		if(vis[child])
		{
			if(b[node] + b[child] != 0)
			{
				int x = (w - a[node] - a[child]) / (b[node] + b[child]) ;
				ans[node] = a[node] + x * b[node] ;
				known = node ;
			}
			else if(a[node] + a[child] != w)
				flag = false ;
			continue ;
		}
		a[child] = w - a[node] , b[child] = -1 * b[node] ;
		dfs(child) ;
	}
}

void dfs2(int node)
{
	vis[node] = 2 ;
	for(auto &childd : adj[node])
	{
		int child = childd.first , w = childd.second ;
		if(vis[child] == 2)
		{
			if(ans[node] + ans[child] != w)
				flag = false ;
			continue ;
		}
		ans[child] = w - ans[node] ;
		dfs2(child) ;
	}
}

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n>>m ;
	for(int i = 0 ; i < m ; ++i)
	{
		int x , y , z ;
		cin>>x>>y>>z ;
		z *= 2 ;
		adj[x].emplace_back(y , z) ;
		adj[y].emplace_back(x , z) ;
	}
	for(int i = 1 ; i <= n ; ++i)
	{
		if(vis[i])
			continue ;
		v.clear() , known = -1 ;
		b[i] = 1 ;
		dfs(i) ;
		if(!flag)
			return cout<<"NO\n" , 0 ;
		if(known == -1)
		{
			sort(v.begin() , v.end()) ;
			ans[i] = v[v.size()/2] ;
			known = i ;
		}
		dfs2(known) ;
		if(!flag)
			return cout<<"NO\n" , 0 ;
	}
	cout<<"YES\n" ;
	for(int i = 1 ; i <= n ; ++i)
		cout<<ans[i] / 2.00<<" " ;
	cout<<"\n" ;
	return 0 ;
}		

• Subtask 1: 5 / 5
• Subtask 2: 12 / 12
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 42 / 42