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Submission #1106537

# Submission time Handle Problem Language Result Execution time Memory
1106537 2024-10-30T15:21:37 Z LOLOLO Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 529 ms 190008 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (ll)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())

const int N = 1e6 + 60;
vector <int> ed[N];
int f[N], n, m, t, on[N], dep[N];

void dfs(int u, int v) {
    vector <int> cost;
    for (auto x : ed[u]) {
        if (x == v)
            continue;

        if (v) {
            f[x] = f[u] + sz(ed[u]) - 2;
        }

        dfs(x, u);
        if (on[x])
            on[u] = 1;

        cost.pb(f[x]);
    }

    sort(all(cost), greater <int> ());
    if (sz(cost) > 1) {
        f[u] = cost[1];
    }

    f[u] += (sz(ed[u]) > 1);
}

vector <pair <int, int>> save;

void run(int u, int v) {
    if (u == t)
        return;

    for (auto x : ed[u]) {
        if (x == v)
            continue;

        dep[x] = dep[u] + 1;
        if (on[u] && !on[x]) {
            save.pb({dep[x], f[x] + (u == m)});
        } else {
            run(x, u);
        }
    }
}

bool check(int m) {
    int need = 0;
    for (auto x : save) {
        if (need > x.f)
            return 0;

        if (need + x.s > m) {
            need++;
        }
    }

    return need <= m;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> t >> m;

    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        ed[a].pb(b);
        ed[b].pb(a);
    }

    if (t == m) {
        cout << 0 << '\n';
        return 0;
    }
    on[m] = 1;
    dep[m] = -1;

    dfs(t, 0);
    run(m, 0);
    sort(all(save));

    int l = 0, r = 1e8, ans = 0;
    while (l <= r) {
        int m = (l + r) / 2;
        if (check(m)) {
            ans = m;
            r = m - 1;
        } else {
            l = m + 1;
        }
    }

    cout << ans << '\n';
    return 0;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 29264 KB Output is correct
2 Correct 5 ms 29264 KB Output is correct
3 Correct 5 ms 29432 KB Output is correct
4 Correct 5 ms 29264 KB Output is correct
5 Correct 6 ms 29264 KB Output is correct
6 Correct 5 ms 29124 KB Output is correct
7 Correct 5 ms 29264 KB Output is correct
8 Correct 6 ms 29356 KB Output is correct
9 Correct 4 ms 29264 KB Output is correct
10 Correct 5 ms 29128 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 191 ms 62544 KB Output is correct
2 Correct 196 ms 71432 KB Output is correct
3 Correct 529 ms 78872 KB Output is correct
4 Correct 197 ms 53832 KB Output is correct
5 Correct 495 ms 77024 KB Output is correct
6 Correct 480 ms 78984 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 29264 KB Output is correct
2 Correct 5 ms 29264 KB Output is correct
3 Correct 5 ms 29432 KB Output is correct
4 Correct 5 ms 29264 KB Output is correct
5 Correct 6 ms 29264 KB Output is correct
6 Correct 5 ms 29124 KB Output is correct
7 Correct 5 ms 29264 KB Output is correct
8 Correct 6 ms 29356 KB Output is correct
9 Correct 4 ms 29264 KB Output is correct
10 Correct 5 ms 29128 KB Output is correct
11 Correct 5 ms 29264 KB Output is correct
12 Correct 5 ms 29264 KB Output is correct
13 Correct 5 ms 29264 KB Output is correct
14 Correct 5 ms 29488 KB Output is correct
15 Correct 5 ms 29264 KB Output is correct
16 Correct 5 ms 29264 KB Output is correct
17 Correct 6 ms 29264 KB Output is correct
18 Correct 5 ms 29432 KB Output is correct
19 Correct 5 ms 29264 KB Output is correct
20 Correct 5 ms 29384 KB Output is correct
21 Correct 5 ms 29432 KB Output is correct
22 Correct 4 ms 29264 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 29264 KB Output is correct
2 Correct 5 ms 29264 KB Output is correct
3 Correct 5 ms 29432 KB Output is correct
4 Correct 5 ms 29264 KB Output is correct
5 Correct 6 ms 29264 KB Output is correct
6 Correct 5 ms 29124 KB Output is correct
7 Correct 5 ms 29264 KB Output is correct
8 Correct 6 ms 29356 KB Output is correct
9 Correct 4 ms 29264 KB Output is correct
10 Correct 5 ms 29128 KB Output is correct
11 Correct 191 ms 62544 KB Output is correct
12 Correct 196 ms 71432 KB Output is correct
13 Correct 529 ms 78872 KB Output is correct
14 Correct 197 ms 53832 KB Output is correct
15 Correct 495 ms 77024 KB Output is correct
16 Correct 480 ms 78984 KB Output is correct
17 Correct 5 ms 29264 KB Output is correct
18 Correct 5 ms 29264 KB Output is correct
19 Correct 5 ms 29264 KB Output is correct
20 Correct 5 ms 29488 KB Output is correct
21 Correct 5 ms 29264 KB Output is correct
22 Correct 5 ms 29264 KB Output is correct
23 Correct 6 ms 29264 KB Output is correct
24 Correct 5 ms 29432 KB Output is correct
25 Correct 5 ms 29264 KB Output is correct
26 Correct 5 ms 29384 KB Output is correct
27 Correct 5 ms 29432 KB Output is correct
28 Correct 4 ms 29264 KB Output is correct
29 Correct 5 ms 29264 KB Output is correct
30 Correct 197 ms 75908 KB Output is correct
31 Correct 211 ms 78036 KB Output is correct
32 Correct 347 ms 190008 KB Output is correct
33 Correct 296 ms 185672 KB Output is correct
34 Correct 507 ms 79176 KB Output is correct
35 Correct 453 ms 79020 KB Output is correct
36 Correct 513 ms 95300 KB Output is correct
37 Correct 516 ms 95164 KB Output is correct
38 Correct 411 ms 96052 KB Output is correct
39 Correct 404 ms 96016 KB Output is correct
40 Correct 401 ms 95948 KB Output is correct