Submission #46413

#	Time	Username	Problem	Language	Result	Execution time	Memory
46413		RockyB	Mousetrap (CEOI17_mousetrap)	C++17	0 / 100	407 ms	61160 KiB

mousetrap

/// In The Name Of God
 
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
#include <bits/stdc++.h>
 
#define f first
#define s second
 
#define pb push_back
#define pp pop_back
#define mp make_pair
 
#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()
 
#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
 
#define nl '\n'
#define ioi exit(0);
 
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
 
const int N = (int)1e6 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;
 
const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
 
using namespace std;
 
int n, t, m;
vector <int> g[N];

int sz[N], deep[N];
void dfs(int v = m, int p = -1) {
	sz[v] = 1;
	for (auto to : g[v]) {
		if (to != p) {
			dfs(to, v);
			sz[v] += sz[to];
			deep[v] = max(deep[v], deep[to] + 1);
		}
	}
}
bool cmp(int x, int y) {
	return deep[x] > deep[y];
	return sz[x] > sz[y];
}

int calc(int v = m, int p = t) {
	vector <int> go;
	for (auto to : g[v]) {
		if (to == p) continue;
		go.pb(to);
	}
	sort(all(go), cmp);
	if (sz(go) == 1) {
		//cerr << v << ' ' << 1 << nl;
		return 1;
	}
	int res = sz(go) - 1;
	if (sz(go) > 1) {
		res += calc(go[1], v) + 1;
	}	
	return res;
}
int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
	#endif
	Kazakhstan
	cin >> n >> t >> m;
	for (int i = 1; i < n; i++) {
		int v, u;
		cin >> v >> u;
		g[v].pb(u);
		g[u].pb(v);
	}
	dfs();
	cout << calc();
	ioi
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 25
• Subtask 3: 0 / 20
• Subtask 4: 0 / 35