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Submission #704594

# Submission time Handle Problem Language Result Execution time Memory
704594 2023-03-02T11:31:29 Z amirhoseinfar1385 Mousetrap (CEOI17_mousetrap) C++17
45 / 100
 850 ms 115576 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 23 ms 47220 KB Output is correct
2 Correct 23 ms 47208 KB Output is correct
3 Correct 22 ms 47228 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 23 ms 47292 KB Output is correct
6 Correct 23 ms 47316 KB Output is correct
7 Correct 27 ms 47276 KB Output is correct
8 Correct 24 ms 47212 KB Output is correct
9 Correct 23 ms 47284 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 330 ms 109904 KB Output is correct
2 Correct 314 ms 103552 KB Output is correct
3 Correct 850 ms 115576 KB Output is correct
4 Correct 411 ms 81384 KB Output is correct
5 Correct 840 ms 115376 KB Output is correct
6 Correct 833 ms 115568 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 47220 KB Output is correct
2 Correct 23 ms 47208 KB Output is correct
3 Correct 22 ms 47228 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 23 ms 47292 KB Output is correct
6 Correct 23 ms 47316 KB Output is correct
7 Correct 27 ms 47276 KB Output is correct
8 Correct 24 ms 47212 KB Output is correct
9 Correct 23 ms 47284 KB Output is correct
10 Correct 22 ms 47316 KB Output is correct
11 Incorrect 21 ms 47316 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 47220 KB Output is correct
2 Correct 23 ms 47208 KB Output is correct
3 Correct 22 ms 47228 KB Output is correct
4 Correct 22 ms 47316 KB Output is correct
5 Correct 23 ms 47292 KB Output is correct
6 Correct 23 ms 47316 KB Output is correct
7 Correct 27 ms 47276 KB Output is correct
8 Correct 24 ms 47212 KB Output is correct
9 Correct 23 ms 47284 KB Output is correct
10 Correct 22 ms 47316 KB Output is correct
11 Correct 330 ms 109904 KB Output is correct
12 Correct 314 ms 103552 KB Output is correct
13 Correct 850 ms 115576 KB Output is correct
14 Correct 411 ms 81384 KB Output is correct
15 Correct 840 ms 115376 KB Output is correct
16 Correct 833 ms 115568 KB Output is correct
17 Incorrect 21 ms 47316 KB Output isn't correct
18 Halted 0 ms 0 KB -