Submission #365381

#	Time	Username	Problem	Language	Result	Execution time	Memory
365381		FatihSolak	Mag (COCI16_mag)	C++17	120 / 120	505 ms	149100 KiB

mag

#include <bits/stdc++.h>
#define N 1000005
using namespace std;
vector<int> adj[N];
int arr[N];
int down[N];
int down2[N];
int d[N];
int up[N];
int maxi = 0,mini = 1e9;
void dfs(int v,int p){
	for(auto u:adj[v]){
		if(u == p)continue;
		dfs(u,v);
		if(arr[u] == 1){
			down[v] = max(down[v],down[u] + 1);
			if(down[v] == down[u] + 1)d[v] = u;
		}
	}
	for(auto u:adj[v]){
		if(u == p)continue;
		if(d[v] != u && arr[u] == 1){
			down2[v] = max(down2[v],down[u]+1);
		}
	}
}
void dfs2(int v,int p){
	if(arr[p] == 1){
		up[v] = up[p] + 1;
		if(arr[v] == 1 && d[p] == v){
			up[v] = max(up[v], down2[p]+1);
		}
		else up[v] = max(up[v], down[p]+1);
	}
	for(auto u:adj[v]){
		if(u == p)continue;
		dfs2(u,v);
	}
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	//freopen("in.txt","r",stdin);
	//freopen("out.txt","w",stdout);
	int n;
	cin >> n;
	for(int i=1;i<n;i++){
		int u,v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	for(int i=1;i<=n;i++){
		cin >> arr[i];
	}
	dfs(1,0);
	dfs2(1,0);
	for(int i=1;i<=n;i++){
		if(arr[i] == 1){
			maxi = max(maxi,2*(1+down[i]+up[i]));
		}
		if(arr[i] == 2){
			maxi = max(maxi,1+down[i]+up[i]);
		}
		mini = min(mini,arr[i]);
	}
	if(maxi == 0){
		cout << mini << "/" <<1;
	}
	else if(maxi & 1){
		cout << 2 << "/" << maxi;
	}
	else cout << 1 << "/" << maxi/2;
}

• Subtask 1: 12 / 12
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 12 / 12
• Subtask 5: 12 / 12
• Subtask 6: 12 / 12
• Subtask 7: 12 / 12
• Subtask 8: 12 / 12
• Subtask 9: 12 / 12
• Subtask 10: 12 / 12