Submission #847036

#	Time	Username	Problem	Language	Result	Execution time	Memory
847036		GrandTiger1729	Birthday gift (IZhO18_treearray)	C++17	56 / 100	4043 ms	38492 KiB

treearray

#include <bits/stdc++.h>
using namespace std;

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int n, m, q; cin >> n >> m >> q;
    vector<vector<int>> g(n);
    for (int i = 0; i < n - 1; i++)
    {
        int u, v; cin >> u >> v;
        u--, v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    vector<int> in(n), out(n);
    vector<vector<int>> up(n, vector<int>(__lg(n) + 1));
    {
        int t = 0;
        vector<bool> vis(n);
        function<void(int)> dfs = [&](int u)
        {
            vis[u] = 1;
            in[u] = t++;
            for (int i =  1; i <= __lg(n); i++)
                up[u][i] = up[up[u][i - 1]][i - 1];
            for (auto &v : g[u])
            {
                if (vis[v])
                    continue;
                up[v][0] = u;
                dfs(v);
            }
            out[u] = t;
        };
        dfs(0);
    }
    auto anc = [&](int u, int v) -> bool
    {
        return in[u] <= in[v] && out[u] >= out[v];
    };
    auto lca = [&](int u, int v) -> int
    {
        if (anc(u, v))
            return u;
        for (int i = __lg(n); i >= 0; i--)
            if (!anc(up[u][i], v))
                u = up[u][i];
        return up[u][0];
    };
    vector<int> a(m);
    for (int i = 0; i < m; i++)
        cin >> a[i], a[i]--;
    while (q--)
    {
        int ty; cin >> ty;
        if (ty == 1)
        {
            int i, u; cin >> i >> u;
            i--, u--;
            a[i] = u;
        }
        else
        {
            int l, r, u; cin >> l >> r >> u;
            l--, u--;
            int ans = -1;
            for (int i = l; i < r; i++)
            {
                if (a[i] == u)
                    ans = i;
            }
            if (ans != -1)
            {
                cout << ans + 1 << ' ' << ans + 1 << '\n';
                continue;
            }
            for (int i = l; i < r - 1; i++)
            {
                if (lca(a[i], a[i + 1]) == u)
                    ans = i;
            }
            if (ans == -1)
                cout << "-1 -1\n";
            else
                cout << ans + 1 << ' ' << ans + 2 << '\n';
        }
    }
    return 0;
}

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 26 / 26
• Subtask 4: 0 / 44