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답안 #47067

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
47067 2018-04-27T06:25:13 Z RockyB Mousetrap (CEOI17_mousetrap) C++17
45 / 100
 1150 ms 60624 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);
	if (super) return solve(jump[v], v, cnt + 1, super) + sz;

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

	int mn = inf;
	

	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 + 1, 1) + cur[i].f + sz);
		}
		else {
			mn = min(mn, solve(jump[v], v, cnt + 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

# 결과 실행 시간 메모리 Grader output
1 Correct 27 ms 27764 KB Output is correct
2 Correct 26 ms 27764 KB Output is correct
3 Correct 26 ms 27952 KB Output is correct
4 Correct 26 ms 27952 KB Output is correct
5 Correct 25 ms 27952 KB Output is correct
6 Correct 27 ms 27952 KB Output is correct
7 Correct 25 ms 27952 KB Output is correct
8 Correct 26 ms 28052 KB Output is correct
9 Correct 26 ms 28052 KB Output is correct
10 Correct 25 ms 28052 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 436 ms 59392 KB Output is correct
2 Correct 513 ms 59392 KB Output is correct
3 Correct 1066 ms 60476 KB Output is correct
4 Correct 489 ms 60476 KB Output is correct
5 Correct 1150 ms 60624 KB Output is correct
6 Correct 1067 ms 60624 KB Output is correct

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 27 ms 27764 KB Output is correct
2 Correct 26 ms 27764 KB Output is correct
3 Correct 26 ms 27952 KB Output is correct
4 Correct 26 ms 27952 KB Output is correct
5 Correct 25 ms 27952 KB Output is correct
6 Correct 27 ms 27952 KB Output is correct
7 Correct 25 ms 27952 KB Output is correct
8 Correct 26 ms 28052 KB Output is correct
9 Correct 26 ms 28052 KB Output is correct
10 Correct 25 ms 28052 KB Output is correct
11 Incorrect 27 ms 60624 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 27 ms 27764 KB Output is correct
2 Correct 26 ms 27764 KB Output is correct
3 Correct 26 ms 27952 KB Output is correct
4 Correct 26 ms 27952 KB Output is correct
5 Correct 25 ms 27952 KB Output is correct
6 Correct 27 ms 27952 KB Output is correct
7 Correct 25 ms 27952 KB Output is correct
8 Correct 26 ms 28052 KB Output is correct
9 Correct 26 ms 28052 KB Output is correct
10 Correct 25 ms 28052 KB Output is correct
11 Correct 436 ms 59392 KB Output is correct
12 Correct 513 ms 59392 KB Output is correct
13 Correct 1066 ms 60476 KB Output is correct
14 Correct 489 ms 60476 KB Output is correct
15 Correct 1150 ms 60624 KB Output is correct
16 Correct 1067 ms 60624 KB Output is correct
17 Incorrect 27 ms 60624 KB Output isn't correct
18 Halted 0 ms 0 KB -