Submission #46400

#	Time	Username	Problem	Language	Result	Execution time	Memory
46400		RockyB	Mousetrap (CEOI17_mousetrap)	C++17	0 / 100	430 ms	59216 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];
void dfs(int v = m, int p = -1) {
	sz[v] = 1;
	for (auto to : g[v]) {
		if (to == p) continue;
		dfs(to, v);
		sz[v] += sz[to];
	}
}

int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
	#endif
	Kazakhstan
	cin >> n >> t >> m;
	if (m == t) {
		assert(0);
		cout << 0, ioi
	}
	for (int i = 1; i < n; i++) {
		int v, u;
		cin >> v >> u;
		g[v].pb(u);
		g[u].pb(v);
	}
	dfs();
	vector <int> a;
	for (auto to : g[m]) {
		if (to == t) {
			continue;
		}
		a.pb(sz[to]);
	}
	sort(all(a), greater<int>());

	if (!sz(a)) {
		assert(0);
	}
	int ans = sz(a);
	if (sz(a) > 1) {
		ans += sz[a[1]] - 1;
	}
	cout << ans;
	ioi
}

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