Submission #127900

#	Time	Username	Problem	Language	Result	Execution time	Memory
127900		shashwatchandra	Torrent (COI16_torrent)	C++17	31 / 100	145 ms	760 KiB

torrent

/*input
17 1 2
1 3
1 4
4 6
6 7
3 8
3 9
3 10
1 13
13 5
13 11
13 12
13 14
14 15
15 16
15 17
14 2
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define int long long 
#define double long double
#define f first
#define s second
#define mp make_pair
#define pb push_back

#define RE(i,n) for (int i = 1; i <= n; i++)
#define RED(i,n) for (int i = n; i > 0; i--)
#define REPS(i,n) for(int i = 1; (i*i) <= n; i++)
#define REP(i,n) for (int i = 0; i < (int)n; i++)
#define FOR(i,a,b) for (int i = a; i < b; i++)
#define REPD(i,n) for (int i = n-1; i >= 0; i--)
#define FORD(i,a,b) for (int i = a; i >= b; i--)

#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define vi vector<int>
#define vvi vector<vi>
#define print(arr) for (auto it = arr.begin(); it != arr.end(); ++it) cout << *it << " "; cout << endl;
#define debug(x) cout << x << endl;
#define debug2(x,y) cout << x << " " << y << endl;
#define debug3(x,y,z) cout << x << " " << y << " " << z << endl;

typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;

const int INF = 1e18+1;
const int MOD = 1e9+7;
const double PI = 3.14159265358979323846264338;

int raise(int a,int n,int m = MOD){
  if(n == 0)return 1;
  if(n == 1)return a;
  int x = 1;
    x *= raise(a,n/2,m);
    x %= m;
    x *= x;
    x %= m;
    if(n%2)x*= a;
    x %= m;
    return x;
}

int floor1(int n,int k){
    if(n%k == 0 || n >= 0)return n/k;
    return (n/k)-1;
}

int ceil1(int n,int k){
    return floor1(n+k-1,k);
}

const int N = 1001;
int n,x,y;
set<int> adj[N];
int vis = 0;
int ans = INF;
vector<pii> edges;

int trynow(int u,int p){
	
	vis--;
	if(adj[u].size() < 2 and p)return 0;
	vector<int> childs;
	for(int v:adj[u]){
		if(v == p)continue;
		childs.pb(trynow(v,u));
	}
	sort(all(childs));reverse(all(childs));
	int res = 0;
	REP(i,childs.size()){
		res = max(res,1+i+childs[i]);
	}
	return res;
}

void delpro(){
	REP(i,n-1){
		int u = edges[i].f;
		int v = edges[i].s;
		//cout << u << " " << v << endl;
		adj[u].erase(v);adj[v].erase(u);
		vis = n;
		int curans = max(trynow(x,0),trynow(y,0));
		if(!vis){
			//cout << "here";
			ans = min(ans,curans);
		}
		adj[u].insert(v);adj[v].insert(u);
	}
}

void solve(){
  	cin >> n >> x >> y;
  	REP(i,n-1){
  		int a,b;
  		cin >> a >> b;
  		adj[a].insert(b);
  		adj[b].insert(a);
  		edges.pb({a,b});
  	}
  	delpro();
  	cout << ans;
}

signed main(){
  ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
  //freopen(".in","r",stdin);freopen(".out","w",stdout);
  int t = 1;
  //cin >> t;
  while(t--){
    solve();
  }
  return 0;
}

• Subtask 1: 31 / 31
• Subtask 2: 0 / 69