#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N=1e5+5;
vector <int> g[N];
int d[N],bl[N],par[N],par2[N];
void dfs(int v,int p){
par[v]=p;
for(auto to : g[v]){
if(to!=p)dfs(to,v);
}
d[p]=max(d[p],d[v]+1);
}
signed main(){
ios_base::sync_with_stdio();
cin.tie(0);cout.tie(0);
int n,t,s;
cin>>n>>t>>s;
for(int i=0;i<n-1;i++){
int u,v;
cin>>u>>v;
g[u].pb(v);
g[v].pb(u);
}
dfs(t,0);
int ans=0;
while(s!=t){
int ind=-1,mx=-1,pos=0,cnt=0;
for(auto to : g[s]){
if(to!=par[s] && to!=par2[s]){
cnt++;
if(d[to]>mx){
mx=d[to];
ind=pos;
}
}
pos++;
}
if(ind!=-1){
ans++;cnt--;
}
pos=0;
int mn=1e7;
for(auto to : g[s]){
if(to!=par[s] && to!=par2[s]){
if(d[to]<mn && pos!=ind){
mn=d[to];
}
}
pos++;
}
if(mn!=1e7){
if(mn>0)ans++;
ans++;
cnt--;
}
ans+=cnt;
par2[par[s]]=s;
s=par[s];
}
cout<<ans<<"\n";
}
/*
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
5724 KB |
Output is correct |
2 |
Correct |
1 ms |
5724 KB |
Output is correct |
3 |
Correct |
2 ms |
5724 KB |
Output is correct |
4 |
Correct |
1 ms |
5724 KB |
Output is correct |
5 |
Incorrect |
1 ms |
5724 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
51 ms |
16232 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
5724 KB |
Output is correct |
2 |
Correct |
1 ms |
5724 KB |
Output is correct |
3 |
Correct |
2 ms |
5724 KB |
Output is correct |
4 |
Correct |
1 ms |
5724 KB |
Output is correct |
5 |
Incorrect |
1 ms |
5724 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
5724 KB |
Output is correct |
2 |
Correct |
1 ms |
5724 KB |
Output is correct |
3 |
Correct |
2 ms |
5724 KB |
Output is correct |
4 |
Correct |
1 ms |
5724 KB |
Output is correct |
5 |
Incorrect |
1 ms |
5724 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |