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Submission #47066

# Submission time Handle Problem Language Result Execution time Memory
47066 2018-04-27T06:20:14 Z RockyB Mousetrap (CEOI17_mousetrap) C++17
45 / 100
 1010 ms 60488 KB 
/// 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;
int dp[N], jump[N];
bool ok[N];

vector <int> g[N];
 
void dfs0(int v = m, int p = -1) {
	if (v == t) ok[v] = 1;
	for (auto to : g[v]) {
		if (to == p) continue;
		dfs0(to, v);
		if (ok[to]) {
			ok[v] = 1;
			jump[v] = to;
		}
	}
}
int dfs(int v = m, int p = t) {
	if (~dp[v]) return dp[v];

	{
		int cnt = 0;
		for (auto to : g[v]) {
			if (to == p) continue;
			++cnt;
		}
		if (cnt <= 1) return dp[v] = cnt;
	}
	
	int id1 = -1, id2 = -1, sz = 0;
	for (auto to : g[v]) {
		if (to == p) continue;
		if (id1 == -1 || dfs(to, v) > dfs(id1, v)) id1 = to;
		++sz;	
	}
	for (auto to : g[v]) {
		if (to == p || to == id1) continue;
		if (id2 == -1 || dfs(to, v) > dfs(id2, v)) id2 = to;
	}
	return dp[v] = dfs(id2, v) + sz;
}

int solve(int v = m, int p = -1, int cnt = 1, bool super = 0) {
	if (v == t) {
		return 0;
	}
	if (!ok[v]) return dfs(v, p);

	int sz = 0;
	vector < pair <int, int> > cur;
	for (auto to : g[v]) {
		if (to == p || ok[to]) continue;
		cur.pb({dfs(to, v), to});
		++sz;	
	}

	if (!sz) return solve(jump[v], v, cnt + 1, super);

	sort(all(cur));
	reverse(all(cur));	

	int mn = inf;
	if (super) return solve(jump[v], v, cnt + 1, super) + sz;
	if (cnt >= sz) return solve(jump[v], v, cnt - sz + 1, super) + sz;


	for (int i = 1; i <= min(sz, cnt); i++) {
		if (i == min(sz, cnt)) {
			if (sz <= cnt) mn = min(mn, solve(jump[v], v, cnt - i + 1, super) + sz);
			else mn = min(mn, solve(jump[v], v, cnt - i + 1, 1) + cur[i].f + sz);
		}
		else {
			mn = min(mn, solve(jump[v], v, cnt - i + 1, 1) + sz + cur[i].f);
		}
	}
	return mn;
}
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);
	}
	dfs0();
	memset(dp, -1, sizeof(dp));
	cout << solve();
	ioi
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 27768 KB Output is correct
2 Correct 25 ms 27876 KB Output is correct
3 Correct 26 ms 27884 KB Output is correct
4 Correct 25 ms 27884 KB Output is correct
5 Correct 26 ms 27884 KB Output is correct
6 Correct 33 ms 28060 KB Output is correct
7 Correct 28 ms 28060 KB Output is correct
8 Correct 25 ms 28060 KB Output is correct
9 Correct 25 ms 28060 KB Output is correct
10 Correct 24 ms 28060 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 422 ms 59432 KB Output is correct
2 Correct 385 ms 59432 KB Output is correct
3 Correct 995 ms 60412 KB Output is correct
4 Correct 457 ms 60412 KB Output is correct
5 Correct 990 ms 60488 KB Output is correct
6 Correct 1010 ms 60488 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 27768 KB Output is correct
2 Correct 25 ms 27876 KB Output is correct
3 Correct 26 ms 27884 KB Output is correct
4 Correct 25 ms 27884 KB Output is correct
5 Correct 26 ms 27884 KB Output is correct
6 Correct 33 ms 28060 KB Output is correct
7 Correct 28 ms 28060 KB Output is correct
8 Correct 25 ms 28060 KB Output is correct
9 Correct 25 ms 28060 KB Output is correct
10 Correct 24 ms 28060 KB Output is correct
11 Incorrect 26 ms 60488 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 27768 KB Output is correct
2 Correct 25 ms 27876 KB Output is correct
3 Correct 26 ms 27884 KB Output is correct
4 Correct 25 ms 27884 KB Output is correct
5 Correct 26 ms 27884 KB Output is correct
6 Correct 33 ms 28060 KB Output is correct
7 Correct 28 ms 28060 KB Output is correct
8 Correct 25 ms 28060 KB Output is correct
9 Correct 25 ms 28060 KB Output is correct
10 Correct 24 ms 28060 KB Output is correct
11 Correct 422 ms 59432 KB Output is correct
12 Correct 385 ms 59432 KB Output is correct
13 Correct 995 ms 60412 KB Output is correct
14 Correct 457 ms 60412 KB Output is correct
15 Correct 990 ms 60488 KB Output is correct
16 Correct 1010 ms 60488 KB Output is correct
17 Incorrect 26 ms 60488 KB Output isn't correct
18 Halted 0 ms 0 KB -