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Submission #868745

# Submission time Handle Problem Language Result Execution time Memory
868745 2023-11-01T22:04:20 Z WLZ Cat Exercise (JOI23_ho_t4) C++17
100 / 100
 195 ms 62040 KB 
#include <bits/stdc++.h>
using namespace std;

// https://codeforces.com/blog/entry/74847
class lowest_common_ancestor {
    private:
    std::vector< std::vector<int> > g;
    std::vector<int> p, jump, d;

    void dfs(int u) {
        if (d[p[u]] - d[jump[p[u]]] == d[jump[p[u]]] - d[jump[jump[p[u]]]]) jump[u] = jump[jump[p[u]]];

        for (auto v : g[u]) {
            if (v == p[u]) continue;
            jump[v] = p[v] = u;
            d[v] = d[u] + 1;
            dfs(v);
        }
    }

    public:
    lowest_common_ancestor(const std::vector< std::vector<int> > &_g, int root) : g(_g) {
        int n = (int) g.size();
        p.resize(n); jump.resize(n); d.assign(n, 0);
        p[root] = root;
        dfs(root);
    }

    int kth_ancestor(int u, int k) const {
        int v = u;
        while (d[u] - d[v] < k) {
            if (d[u] - d[jump[v]] < k) v = jump[v];
            else v = p[v];
        }
        return v;
    }

    int query(int u, int v) const {
        if (d[u] < d[v]) return query(v, u);
        u = kth_ancestor(u, d[u] - d[v]);
        while (u != v) {
            if (jump[u] == jump[v]) u = p[u], v = p[v];
            else u = jump[u], v = jump[v];
        }
        return u;
    }

    int depth(int u) const { return d[u]; }

    int dist(int u, int v) const { return d[u] + d[v] - 2 * d[query(u, v)]; }
};

class union_find {
    private:
    int n;
    std::vector<int> p, h, largest;

    public:
    union_find() : n(0) {}
    explicit union_find(const std::vector<int> &_h) : n(static_cast<int>(_h.size())), p(n, -1), h(_h), largest(n) {
        std::iota(largest.begin(), largest.end(), 0);
    }

    int root(int a) { return p[a] < 0 ? a : (p[a] = root(p[a])); }

    bool connected(int a, int b) { return root(a) == root(b); }

    int connect(int a, int b) {
        a = root(a); b = root(b);
        if (a == b) return a;
        if (p[a] > p[a]) std::swap(a, b);
        p[a] += p[b]; p[b] = a;
        largest[a] = h[largest[a]] > h[largest[b]] ? largest[a] : largest[b];
        return a;
    }

    int size() const { return n; }

    int size(int a) { return -p[root(a)]; }

    int tallest(int a) { return largest[root(a)]; }
};

int main() {
    ios::sync_with_stdio(false); cin.tie(0);

    int n; cin >> n;
    vector<int> h(n + 1);
    for (int i = 1; i <= n; i++) cin >> h[i];

    vector g(n + 1, vector<int>());
    for (int i = 0; i < n - 1; i++) {
        int a, b; cin >> a >> b;
        g[a].push_back(b); g[b].push_back(a);
    }

    vector<int> ord(n);
    iota(ord.begin(), ord.end(), 1);
    sort(ord.begin(), ord.end(), [&](int a, int b) { return h[a] < h[b]; }); 

    vector<bool> used(n + 1, false);
    vector g2(n + 1, vector<int>());

    union_find uf(h);
    for (const int &u : ord) {
        used[u] = true;
        for (const int &v : g[u]) {
            if (used[v]) {
                g2[u].push_back(uf.tallest(v));
                uf.connect(u, v);
            }
        }
    }

    lowest_common_ancestor lca(g, ord[n - 1]);

    function<long long(int)> solve = [&](int u) {
        long long ans = 0;
        for (const int &v : g2[u]) ans = max(ans, lca.dist(u, v) + solve(v));
        return ans;
    };

    cout << solve(ord[n - 1]) << '\n';

    return 0;
}

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 460 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 460 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 3 ms 1880 KB Output is correct
19 Correct 3 ms 1880 KB Output is correct
20 Correct 3 ms 2136 KB Output is correct
21 Correct 3 ms 1372 KB Output is correct
22 Correct 3 ms 1492 KB Output is correct
23 Correct 3 ms 1372 KB Output is correct
24 Correct 3 ms 1372 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 460 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 3 ms 1880 KB Output is correct
19 Correct 3 ms 1880 KB Output is correct
20 Correct 3 ms 2136 KB Output is correct
21 Correct 3 ms 1372 KB Output is correct
22 Correct 3 ms 1492 KB Output is correct
23 Correct 3 ms 1372 KB Output is correct
24 Correct 3 ms 1372 KB Output is correct
25 Correct 1 ms 348 KB Output is correct
26 Correct 3 ms 1808 KB Output is correct
27 Correct 3 ms 1628 KB Output is correct
28 Correct 3 ms 1628 KB Output is correct
29 Correct 3 ms 1628 KB Output is correct
30 Correct 3 ms 1292 KB Output is correct
31 Correct 3 ms 1372 KB Output is correct
32 Correct 3 ms 1372 KB Output is correct
33 Correct 3 ms 1372 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 460 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 3 ms 1880 KB Output is correct
19 Correct 3 ms 1880 KB Output is correct
20 Correct 3 ms 2136 KB Output is correct
21 Correct 3 ms 1372 KB Output is correct
22 Correct 3 ms 1492 KB Output is correct
23 Correct 3 ms 1372 KB Output is correct
24 Correct 3 ms 1372 KB Output is correct
25 Correct 141 ms 62040 KB Output is correct
26 Correct 115 ms 59744 KB Output is correct
27 Correct 112 ms 59824 KB Output is correct
28 Correct 148 ms 45776 KB Output is correct
29 Correct 170 ms 46780 KB Output is correct
30 Correct 144 ms 46932 KB Output is correct
31 Correct 130 ms 46792 KB Output is correct

Subtask #6
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 460 KB Output is correct
3 Correct 133 ms 42204 KB Output is correct
4 Correct 136 ms 42448 KB Output is correct
5 Correct 145 ms 42100 KB Output is correct

Subtask #7
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 456 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 460 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 3 ms 1880 KB Output is correct
19 Correct 3 ms 1880 KB Output is correct
20 Correct 3 ms 2136 KB Output is correct
21 Correct 3 ms 1372 KB Output is correct
22 Correct 3 ms 1492 KB Output is correct
23 Correct 3 ms 1372 KB Output is correct
24 Correct 3 ms 1372 KB Output is correct
25 Correct 1 ms 348 KB Output is correct
26 Correct 3 ms 1808 KB Output is correct
27 Correct 3 ms 1628 KB Output is correct
28 Correct 3 ms 1628 KB Output is correct
29 Correct 3 ms 1628 KB Output is correct
30 Correct 3 ms 1292 KB Output is correct
31 Correct 3 ms 1372 KB Output is correct
32 Correct 3 ms 1372 KB Output is correct
33 Correct 3 ms 1372 KB Output is correct
34 Correct 141 ms 62040 KB Output is correct
35 Correct 115 ms 59744 KB Output is correct
36 Correct 112 ms 59824 KB Output is correct
37 Correct 148 ms 45776 KB Output is correct
38 Correct 170 ms 46780 KB Output is correct
39 Correct 144 ms 46932 KB Output is correct
40 Correct 130 ms 46792 KB Output is correct
41 Correct 0 ms 348 KB Output is correct
42 Correct 0 ms 460 KB Output is correct
43 Correct 133 ms 42204 KB Output is correct
44 Correct 136 ms 42448 KB Output is correct
45 Correct 145 ms 42100 KB Output is correct
46 Correct 195 ms 55536 KB Output is correct
47 Correct 193 ms 55412 KB Output is correct
48 Correct 191 ms 55380 KB Output is correct
49 Correct 181 ms 55384 KB Output is correct
50 Correct 185 ms 41364 KB Output is correct
51 Correct 172 ms 41300 KB Output is correct
52 Correct 169 ms 41300 KB Output is correct
53 Correct 173 ms 41292 KB Output is correct