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Submission #704595

# Submission time Handle Problem Language Result Execution time Memory
704595 2023-03-02T11:31:53 Z amirhoseinfar1385 Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 919 ms 207644 KB 
#include<bits/stdc++.h>
using namespace std;

const int maxn=1000000+5;
vector<int>adj[maxn],alldp[maxn];
int par[maxn],vis[maxn],n,t,m,dp[maxn],ted[maxn],mainres;
int val[maxn],high[maxn];

struct compare
{
    bool operator()(const pair<int,int> & a, const pair<int,int> & b)
    {
        if(a.first==b.first){
        	return high[a.second]>high[b.second];
        }
        return a.first>b.first;
    }
};

priority_queue<pair<int,int>,vector<pair<int,int>>,compare>pq;


void dfs(int u,int para=0){
	par[u]=para;
	high[u]=high[para]+1;
	for(int x:adj[u])
	{
		if(x!=para){
			dfs(x,u);
			vis[u]|=vis[x];
			if(vis[x]==0){
				ted[u]++;
				alldp[u].push_back(dp[x]);
			}	
		}
	}
	if((int)alldp[u].size()>0){
		if((int)alldp[u].size()==1){
			dp[u]=2;
		}
		else{
			sort(alldp[u].begin(),alldp[u].end());
			int maxa1=alldp[u].back(),maxa2=alldp[u][(int)alldp[u].size()-2];
			dp[u]=maxa2+ted[u]-1;
			dp[u]++;
		}
	}	
	else{
		dp[u]=1;
	}
}

void solve(int had){
	int allted=0,now=had;
	while(now!=t){
		//cout<<"1 "<<now<<endl;
		allted+=ted[now];
		now=par[now];
	}
	int fted=allted;
	now=had;
	int unnow=1;
	while(now!=t){
		int ffted=allted;
		for(int i=(int)alldp[now].size()-1;i>=0;i--){
			int x=alldp[now][i]+allted-1+(int)pq.size();
			if((int)pq.size()<unnow){
				pq.push(make_pair(x,now));
				val[now]++;
				allted--;
			}
			else{
				pair<int,int> y=pq.top();
				if(y.first<=x){
					pq.pop();
					pq.push(make_pair(x,now));
					val[y.second]--;
					val[now]++;
					allted--;
					if(y.second==now){
						allted++;
					}
				}
			}
		}
		allted=ffted-ted[now];
		now=par[now];
		unnow++;
	}
	allted=fted;
	int resa=(int)pq.size();
	now=had;
	int fn=0;
	while(now!=t){
		for(int i=0;i<(int)alldp[now].size()-(val[now]-fn);i++){
			int x=alldp[now][i]+allted-1;
		//	cout<<now<<" asd "<<x<<"\n";
			resa=max(resa,x+fn);
		}
		allted-=ted[now];
		fn=val[now];
		val[par[now]]+=val[now];
		now=par[now];
	}
	mainres=resa;
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>t>>m;
	for(int i=0;i<n-1;i++){
		int u,v;
		cin>>u>>v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	vis[m]=1;
	dfs(t);
	solve(m);
	cout<<mainres<<"\n";
}

Compilation message

mousetrap.cpp: In function 'void dfs(int, int)':
mousetrap.cpp:43:8: warning: unused variable 'maxa1' [-Wunused-variable]
   43 |    int maxa1=alldp[u].back(),maxa2=alldp[u][(int)alldp[u].size()-2];
      |        ^~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 47260 KB Output is correct
2 Correct 24 ms 47332 KB Output is correct
3 Correct 22 ms 47300 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 22 ms 47208 KB Output is correct
6 Correct 21 ms 47284 KB Output is correct
7 Correct 23 ms 47284 KB Output is correct
8 Correct 21 ms 47308 KB Output is correct
9 Correct 23 ms 47224 KB Output is correct
10 Correct 22 ms 47316 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 389 ms 109808 KB Output is correct
2 Correct 319 ms 103736 KB Output is correct
3 Correct 896 ms 115396 KB Output is correct
4 Correct 403 ms 81304 KB Output is correct
5 Correct 859 ms 115396 KB Output is correct
6 Correct 860 ms 115720 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 47260 KB Output is correct
2 Correct 24 ms 47332 KB Output is correct
3 Correct 22 ms 47300 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 22 ms 47208 KB Output is correct
6 Correct 21 ms 47284 KB Output is correct
7 Correct 23 ms 47284 KB Output is correct
8 Correct 21 ms 47308 KB Output is correct
9 Correct 23 ms 47224 KB Output is correct
10 Correct 22 ms 47316 KB Output is correct
11 Correct 25 ms 47316 KB Output is correct
12 Correct 23 ms 47296 KB Output is correct
13 Correct 23 ms 47296 KB Output is correct
14 Correct 24 ms 47428 KB Output is correct
15 Correct 22 ms 47444 KB Output is correct
16 Correct 23 ms 47344 KB Output is correct
17 Correct 23 ms 47356 KB Output is correct
18 Correct 23 ms 47284 KB Output is correct
19 Correct 29 ms 47276 KB Output is correct
20 Correct 28 ms 47404 KB Output is correct
21 Correct 24 ms 47360 KB Output is correct
22 Correct 26 ms 47368 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 47260 KB Output is correct
2 Correct 24 ms 47332 KB Output is correct
3 Correct 22 ms 47300 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 22 ms 47208 KB Output is correct
6 Correct 21 ms 47284 KB Output is correct
7 Correct 23 ms 47284 KB Output is correct
8 Correct 21 ms 47308 KB Output is correct
9 Correct 23 ms 47224 KB Output is correct
10 Correct 22 ms 47316 KB Output is correct
11 Correct 389 ms 109808 KB Output is correct
12 Correct 319 ms 103736 KB Output is correct
13 Correct 896 ms 115396 KB Output is correct
14 Correct 403 ms 81304 KB Output is correct
15 Correct 859 ms 115396 KB Output is correct
16 Correct 860 ms 115720 KB Output is correct
17 Correct 25 ms 47316 KB Output is correct
18 Correct 23 ms 47296 KB Output is correct
19 Correct 23 ms 47296 KB Output is correct
20 Correct 24 ms 47428 KB Output is correct
21 Correct 22 ms 47444 KB Output is correct
22 Correct 23 ms 47344 KB Output is correct
23 Correct 23 ms 47356 KB Output is correct
24 Correct 23 ms 47284 KB Output is correct
25 Correct 29 ms 47276 KB Output is correct
26 Correct 28 ms 47404 KB Output is correct
27 Correct 24 ms 47360 KB Output is correct
28 Correct 26 ms 47368 KB Output is correct
29 Correct 23 ms 47220 KB Output is correct
30 Correct 324 ms 110224 KB Output is correct
31 Correct 345 ms 110340 KB Output is correct
32 Correct 312 ms 176572 KB Output is correct
33 Correct 345 ms 207644 KB Output is correct
34 Correct 919 ms 115544 KB Output is correct
35 Correct 893 ms 115644 KB Output is correct
36 Correct 868 ms 137304 KB Output is correct
37 Correct 848 ms 137288 KB Output is correct
38 Correct 657 ms 125960 KB Output is correct
39 Correct 620 ms 126076 KB Output is correct
40 Correct 607 ms 125912 KB Output is correct