oj.uz

답안 #668107

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
668107 2022-12-02T18:45:41 Z tibinyte Lampice (COCI19_lampice) C++17
73 / 110
 3381 ms 10220 KB 
#include <bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 9;

int add(int x, int y)
{
    x += y;
    if (x >= mod)
    {
        return x - mod;
    }
    return x;
}

int mult(int x, int y)
{
    return (int64_t)x * y % mod;
}

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int random(int st, int dr)
{
    uniform_int_distribution<mt19937::result_type> gen(st, dr);
    return gen(rng);
}
struct lampice
{
    int n;
    vector<vector<int>> g;
    vector<char> colors;
    vector<bool> seen;
    vector<int> sz;
    vector<int> depth;
    vector<int> hashup;
    vector<int> hashdown;
    vector<int> par;
    vector<int> nodes;
    vector<int> neortodox;
    vector<int> dp;
    void init(int _n)
    {
        n = _n;
        g = vector<vector<int>>(n + 1);
        colors = vector<char>(n + 1);
        seen = vector<bool>(n + 1);
        dp = neortodox = nodes = sz = depth = hashup = hashdown = par = vector<int>(n + 1);
    }
    void set_color(int pos, char x)
    {
        colors[pos] = x;
    }
    void add_edge(int a, int b)
    {
        g[a].push_back(b);
        g[b].push_back(a);
    }
    void dfs_size(int node, int parent)
    {
        sz[node] = 1;
        for (auto i : g[node])
        {
            if (i != parent && !seen[i])
            {
                dfs_size(i, node);
                sz[node] += sz[i];
            }
        }
    }
    int find_centroid(int node, int parent, int size)
    {
        for (auto i : g[node])
        {
            if (i != parent && !seen[i] && sz[i] > size / 2)
            {
                return find_centroid(i, node, size);
            }
        }
        return node;
    }
    bool solve(int node, int k)
    {
        int base = random(2, 60);
        int max_depth = 0;
        function<void(int, int, int)> dfs_init = [&](int node, int parent, int d)
        {
            par[node] = parent;
            depth[node] = d;
            dp[node] = 1;
            max_depth = max(max_depth, d);
            for (auto i : g[node])
            {

                if (i != parent && !seen[i])
                {
                    dfs_init(i, node, d + 1);
                    dp[node] = max(dp[node], dp[i] + 1);
                }
            }
            int mx1 = 0, mx2 = 0;
            for (auto i : g[node])
            {
                if (i != parent && !seen[i])
                {
                    if (dp[i] > mx1)
                    {
                        mx2 = mx1;
                        mx1 = dp[i];
                    }
                    else
                    {
                        if (dp[i] > mx2)
                        {
                            mx2 = dp[i];
                        }
                    }
                }
            }
            neortodox[node] = mx1 + mx2 + 1;
        };
        dfs_init(node, 0, 0);
        if (neortodox[node] < k)
        {
            return 0;
        }
        vector<int> power(max_depth + 1);
        power[0] = 1;
        for (int i = 1; i <= max_depth; ++i)
        {
            power[i] = mult(power[i - 1], base);
        }
        function<void(int, int)> compute_hash = [&](int node, int parent)
        {
            hashup[node] = add(mult(base, hashup[parent]), colors[node] - 'a' + 1);
            hashdown[node] = add(hashdown[parent], mult(power[depth[node]], (colors[node] - 'a' + 1)));
            for (auto i : g[node])
            {
                if (i != parent && !seen[i])
                {
                    compute_hash(i, node);
                }
            }
        };
        compute_hash(node, 0);
        function<int(int, int)> get_hashup = [&](int a, int b)
        {
            int c = par[b];
            return add(hashup[a], mod - mult(hashup[c], power[depth[a] - depth[c]]));
        };
        unordered_multiset<int> exista;
        function<void(int, int, int, int)> add_subtree = [&](int node, int parent, int root, int d)
        {
            if (d + d <= k)
            {
                exista.insert(get_hashup(node, root));
            }
            for (auto i : g[node])
            {
                if (i != parent && !seen[i])
                {
                    add_subtree(i, node, root, d + 1);
                }
            }
        };
        function<void(int, int, int, int)> remove_subtree = [&](int node, int parent, int root, int d)
        {
            if (d + d <= k)
            {
                exista.erase(exista.find(get_hashup(node, root)));
            }
            for (auto i : g[node])
            {
                if (i != parent && !seen[i])
                {
                    remove_subtree(i, node, root, d + 1);
                }
            }
        };
        bool este = false;
        int m = 1;
        nodes[1] = node;
        function<void(int, int, int)> dfs = [&](int node, int parent, int d)
        {
            if (este)
            {
                return;
            }
            nodes[++m] = node;
            int t = 2 * d - k;
            int l = k - d;
            if (l >= 0 && t >= 0)
            {
                if (l == 0)
                {
                    if (hashup[node] == hashdown[node])
                    {
                        este = true;
                    }
                }
                else
                {
                    int qui = nodes[m - l];
                    if (hashup[qui] == hashdown[qui] && exista.count(get_hashup(node, nodes[m - l + 1])))
                    {
                        este = true;
                    }
                }
            }
            for (auto i : g[node])
            {
                if (i != parent && !seen[i])
                {
                    dfs(i, node, d + 1);
                }
            }
            --m;
        };
        for (auto i : g[node])
        {
            if (!seen[i])
            {
                add_subtree(i, node, i, 1);
            }
        }
        for (auto i : g[node])
        {
            if (!seen[i])
            {
                remove_subtree(i, node, i, 1);
                dfs(i, node, 2);
                if (este)
                {
                    break;
                }
                add_subtree(i, node, i, 1);
            }
        }
        return este;
    }
    bool decomp(int node, int k)
    {
        dfs_size(node, 0);
        node = find_centroid(node, 0, sz[node]);
        int ans = solve(node, k);
        seen[node] = true;
        for (auto i : g[node])
        {
            if (ans)
            {
                break;
            }
            if (!seen[i])
            {
                ans |= decomp(i, k);
            }
        }
        return ans;
    }
    void reinit()
    {
        seen = vector<bool>(n + 1);
    }
};
int32_t main()
{
    cin.tie(nullptr)->sync_with_stdio(false);
    int n;
    cin >> n;
    lampice g;
    g.init(n);
    for (int i = 1; i <= n; ++i)
    {
        char x;
        cin >> x;
        g.set_color(i, x);
    }
    for (int i = 1; i < n; ++i)
    {
        int u, v;
        cin >> u >> v;
        g.add_edge(u, v);
    }
    int ans = 1;
    int st = 1, dr = n / 2;
    while (st <= dr)
    {
        int mid = (st + dr) / 2;
        if (g.decomp(1, 2 * mid))
        {
            ans = max(ans, 2 * mid);
            st = mid + 1;
        }
        else
        {
            dr = mid - 1;
        }
        g.reinit();
    }
    st = max(1, ans / 2), dr = n / 2;
    while (st <= dr)
    {
        int mid = (st + dr) / 2;
        if (g.decomp(1, 2 * mid + 1))
        {
            ans = max(ans, 2 * mid + 1);
            st = mid + 1;
        }
        else
        {
            dr = mid - 1;
        }
        g.reinit();
    }
    cout << ans;
}

Subtask #1
17.0 / 17.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 6 ms 436 KB Output is correct
3 Correct 26 ms 468 KB Output is correct
4 Correct 31 ms 596 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1558 ms 8000 KB Output is correct
2 Correct 851 ms 8260 KB Output is correct
3 Correct 340 ms 9568 KB Output is correct
4 Correct 420 ms 9992 KB Output is correct
5 Correct 1035 ms 9508 KB Output is correct
6 Correct 223 ms 10220 KB Output is correct

Subtask #3
31.0 / 31.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3381 ms 7356 KB Output is correct
2 Correct 2257 ms 7592 KB Output is correct
3 Correct 2347 ms 7212 KB Output is correct
4 Correct 1757 ms 8284 KB Output is correct
5 Correct 1591 ms 7184 KB Output is correct
6 Correct 1919 ms 6004 KB Output is correct

Subtask #4
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 6 ms 436 KB Output is correct
3 Correct 26 ms 468 KB Output is correct
4 Correct 31 ms 596 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1558 ms 8000 KB Output is correct
9 Correct 851 ms 8260 KB Output is correct
10 Correct 340 ms 9568 KB Output is correct
11 Correct 420 ms 9992 KB Output is correct
12 Correct 1035 ms 9508 KB Output is correct
13 Correct 223 ms 10220 KB Output is correct
14 Correct 3381 ms 7356 KB Output is correct
15 Correct 2257 ms 7592 KB Output is correct
16 Correct 2347 ms 7212 KB Output is correct
17 Correct 1757 ms 8284 KB Output is correct
18 Correct 1591 ms 7184 KB Output is correct
19 Correct 1919 ms 6004 KB Output is correct
20 Correct 1075 ms 6772 KB Output is correct
21 Correct 1000 ms 6796 KB Output is correct
22 Correct 1680 ms 5976 KB Output is correct
23 Correct 493 ms 6860 KB Output is correct
24 Correct 1674 ms 7588 KB Output is correct
25 Correct 1693 ms 7452 KB Output is correct
26 Correct 2442 ms 7388 KB Output is correct
27 Incorrect 2977 ms 6440 KB Output isn't correct
28 Halted 0 ms 0 KB -