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Submission #703154

# Submission time Handle Problem Language Result Execution time Memory
703154 2023-02-26T09:22:40 Z mosaev Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 921 ms 217252 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define N ((ll)1e6+5)
#define M ((ll)1e9+7)
#define fi first
#define se second
ll n, t, m, st[N], ft[N], ct, w[N], dp[N], par[N], h[N], d[N], l, r, md;
vector<ll> v[N];
inline bool mpr(ll x) { return st[x] <= st[m] && ft[x] >= ft[m]; }
void dfs(ll s, ll p) {
	st[s] = ++ct; ll m1, m2; m1 = m2 = -1; h[s] = h[p] + 1;
	for (auto x : v[s]) if (x != p) {
		dfs(x, s); par[x] = s; if (!mpr(x)) {
			d[s]++; if (dp[x] >= m1) swap(m1, m2), m1 = dp[x]; else if (dp[x] >= m2) m2 = dp[x];
		}
	}
	dp[s] = d[s] + (d[s] > 1 ? m2 : 0); if (t == s) d[s] = 0;
	ft[s] = ++ct;
}
void wef(ll s, ll p) {
	w[s] += d[s]; for (auto x : v[s]) if (x != p) {
		w[x] = w[s], dp[x] += w[s]; wef(x, s);
	}
}
inline bool isv(ll x) {
	ll a = m, b, o = 0; while (a != t) {
		b = 0;
		for (auto y : v[a]) 
			if (!mpr(y) && dp[y] + o - b > x) 
				b++, o++;
		if (o > h[m] - h[a] + 1 || o > x) return false;
		a = par[a];
	}return true;
}
int32_t main() {
#define int ll
	ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> t >> m; ll a, b; for (int i = 1; i < n; i++) cin >> a >> b, v[a].push_back(b), v[b].push_back(a);
	dfs(t, 0); 
	wef(t, 0);
	l = -1; r = n; while (r - l > 1) {
		md = (r + l) / 2; if (isv(md)) r = md;
		else l = md;
	}
	cout << r;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23836 KB Output is correct
2 Correct 13 ms 23892 KB Output is correct
3 Correct 13 ms 23820 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23756 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23824 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23816 KB Output is correct
10 Correct 12 ms 23816 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 303 ms 127172 KB Output is correct
2 Correct 276 ms 116832 KB Output is correct
3 Correct 889 ms 129164 KB Output is correct
4 Correct 415 ms 76448 KB Output is correct
5 Correct 878 ms 129080 KB Output is correct
6 Correct 862 ms 129164 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23836 KB Output is correct
2 Correct 13 ms 23892 KB Output is correct
3 Correct 13 ms 23820 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23756 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23824 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23816 KB Output is correct
10 Correct 12 ms 23816 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 12 ms 23940 KB Output is correct
13 Correct 13 ms 23948 KB Output is correct
14 Correct 13 ms 24020 KB Output is correct
15 Correct 13 ms 23892 KB Output is correct
16 Correct 15 ms 23840 KB Output is correct
17 Correct 12 ms 23892 KB Output is correct
18 Correct 13 ms 23892 KB Output is correct
19 Correct 12 ms 23892 KB Output is correct
20 Correct 14 ms 23952 KB Output is correct
21 Correct 12 ms 23892 KB Output is correct
22 Correct 14 ms 23924 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23836 KB Output is correct
2 Correct 13 ms 23892 KB Output is correct
3 Correct 13 ms 23820 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23756 KB Output is correct
6 Correct 14 ms 23764 KB Output is correct
7 Correct 12 ms 23824 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23816 KB Output is correct
10 Correct 12 ms 23816 KB Output is correct
11 Correct 303 ms 127172 KB Output is correct
12 Correct 276 ms 116832 KB Output is correct
13 Correct 889 ms 129164 KB Output is correct
14 Correct 415 ms 76448 KB Output is correct
15 Correct 878 ms 129080 KB Output is correct
16 Correct 862 ms 129164 KB Output is correct
17 Correct 12 ms 23764 KB Output is correct
18 Correct 12 ms 23940 KB Output is correct
19 Correct 13 ms 23948 KB Output is correct
20 Correct 13 ms 24020 KB Output is correct
21 Correct 13 ms 23892 KB Output is correct
22 Correct 15 ms 23840 KB Output is correct
23 Correct 12 ms 23892 KB Output is correct
24 Correct 13 ms 23892 KB Output is correct
25 Correct 12 ms 23892 KB Output is correct
26 Correct 14 ms 23952 KB Output is correct
27 Correct 12 ms 23892 KB Output is correct
28 Correct 14 ms 23924 KB Output is correct
29 Correct 12 ms 23780 KB Output is correct
30 Correct 330 ms 127112 KB Output is correct
31 Correct 334 ms 127096 KB Output is correct
32 Correct 439 ms 209544 KB Output is correct
33 Correct 374 ms 217252 KB Output is correct
34 Correct 880 ms 129124 KB Output is correct
35 Correct 862 ms 129292 KB Output is correct
36 Correct 909 ms 138512 KB Output is correct
37 Correct 921 ms 138576 KB Output is correct
38 Correct 715 ms 136784 KB Output is correct
39 Correct 710 ms 136664 KB Output is correct
40 Correct 745 ms 136764 KB Output is correct