oj.uz

답안 #564087

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
564087 2022-05-18T14:26:46 Z hollwo_pelw Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 795 ms 153900 KB 
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>

using namespace std;
// using namespace __gnu_cxx;
// using namespace __gnu_pbds;

void Hollwo_Pelw();

signed main(){
#ifndef hollwo_pelw_local
	if (fopen("mousetrap.inp", "r"))
		assert(freopen("mousetrap.inp", "r", stdin)), assert(freopen("mousetrap.out", "w", stdout));
#else
	auto start = chrono::steady_clock::now();
#endif
	cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
	int testcases = 1;
	// cin >> testcases;
	for (int test = 1; test <= testcases; test++){
		// cout << "Case #" << test << ": ";
		Hollwo_Pelw();
	}
#ifdef hollwo_pelw_local
	auto end = chrono::steady_clock::now();
	cout << "\nExcution time : " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
#endif
}

const int N = 1e6 + 5;

int n, s, t, deg[N], dp[N], par[N], in_path[N];
vector<int> adj[N];

void find_path(int u, int p) {
    par[u] = p;
    for (int v : adj[u])
        if (v != p) find_path(v, u);
}

void calc_dp(int u, int p) {
    int m1 = 0, m2 = 0;
    for (int v : adj[u]) if (v != p) {
        deg[u] ++;
        calc_dp(v, u);
        int f = dp[v];
        if (f > m1) swap(f, m1);
        if (f > m2) swap(f, m2);
    }
    dp[u] = deg[u] + m2;
}

bool check(int mid) {
    int tot = 0;
    for (int u = s; par[u]; u = par[u])
        tot += deg[u];

    if (tot > mid) return 0;

    for (int u = s, cnt = 0, cur = 1; par[u]; u = par[u], cur ++) {
        int ign = 0;
        for (int v : adj[u]) if (!in_path[v]) {
            ign += tot + dp[v] <= mid;
            cnt += tot + dp[v] >  mid;
        }
        tot -= ign;
        if (cnt > cur) return 0;
    }

    return 1;
}

void Hollwo_Pelw(){
    cin >> n >> t >> s;
    for (int i = 1, u, v; i < n; i++) {
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    find_path(t, 0);

    for (int u = s; u; u = par[u])
        in_path[u] = 1;

    for (int u = s; par[u]; u = par[u]) {
        for (int v : adj[u]) if (!in_path[v]) {
            deg[u] ++;
            calc_dp(v, u);
        }
    }

    int l = 0, r = 2 * n;
    while (l < r) {
        int m = (l + r) >> 1;
        if (check(m))
            r = m;
        else
            l = m + 1;
    }
    cout << l;
}

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 15 ms 23764 KB Output is correct
4 Correct 13 ms 23788 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 15 ms 23832 KB Output is correct
7 Correct 13 ms 23764 KB Output is correct
8 Correct 13 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 289 ms 73580 KB Output is correct
2 Correct 263 ms 69468 KB Output is correct
3 Correct 756 ms 76808 KB Output is correct
4 Correct 356 ms 52372 KB Output is correct
5 Correct 763 ms 76768 KB Output is correct
6 Correct 755 ms 76808 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 15 ms 23764 KB Output is correct
4 Correct 13 ms 23788 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 15 ms 23832 KB Output is correct
7 Correct 13 ms 23764 KB Output is correct
8 Correct 13 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 12 ms 23892 KB Output is correct
13 Correct 12 ms 23856 KB Output is correct
14 Correct 13 ms 23828 KB Output is correct
15 Correct 14 ms 23768 KB Output is correct
16 Correct 13 ms 23764 KB Output is correct
17 Correct 13 ms 23844 KB Output is correct
18 Correct 13 ms 23820 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 15 ms 23816 KB Output is correct
21 Correct 12 ms 23764 KB Output is correct
22 Correct 12 ms 23788 KB Output is correct

Subtask #4
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 15 ms 23764 KB Output is correct
4 Correct 13 ms 23788 KB Output is correct
5 Correct 12 ms 23764 KB Output is correct
6 Correct 15 ms 23832 KB Output is correct
7 Correct 13 ms 23764 KB Output is correct
8 Correct 13 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23812 KB Output is correct
11 Correct 289 ms 73580 KB Output is correct
12 Correct 263 ms 69468 KB Output is correct
13 Correct 756 ms 76808 KB Output is correct
14 Correct 356 ms 52372 KB Output is correct
15 Correct 763 ms 76768 KB Output is correct
16 Correct 755 ms 76808 KB Output is correct
17 Correct 12 ms 23764 KB Output is correct
18 Correct 12 ms 23892 KB Output is correct
19 Correct 12 ms 23856 KB Output is correct
20 Correct 13 ms 23828 KB Output is correct
21 Correct 14 ms 23768 KB Output is correct
22 Correct 13 ms 23764 KB Output is correct
23 Correct 13 ms 23844 KB Output is correct
24 Correct 13 ms 23820 KB Output is correct
25 Correct 12 ms 23764 KB Output is correct
26 Correct 15 ms 23816 KB Output is correct
27 Correct 12 ms 23764 KB Output is correct
28 Correct 12 ms 23788 KB Output is correct
29 Correct 12 ms 23812 KB Output is correct
30 Correct 293 ms 73676 KB Output is correct
31 Correct 274 ms 73704 KB Output is correct
32 Correct 393 ms 94416 KB Output is correct
33 Correct 316 ms 153900 KB Output is correct
34 Correct 781 ms 76704 KB Output is correct
35 Correct 766 ms 76696 KB Output is correct
36 Correct 795 ms 79004 KB Output is correct
37 Correct 789 ms 78892 KB Output is correct
38 Correct 552 ms 78424 KB Output is correct
39 Correct 557 ms 78572 KB Output is correct
40 Correct 551 ms 78680 KB Output is correct