Submission #894465

#	Time	Username	Problem	Language	Result	Execution time	Memory
894465		nahco314	Birthday gift (IZhO18_treearray)	C++14	100 / 100	1734 ms	96304 KiB

treearray

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

void dfs(int v, int p, int d, vector<vector<int>>& g, vector<int>& prev, vector<int>& dist) {
    prev[v] = p;
    dist[v] = d;
    for (int nxt : g[v]) {
        if (nxt == p) continue;
        dfs(nxt, v, d + 1, g, prev, dist);
    }
}

int lca(int a, int b, vector<vector<int>>& prevs, vector<int>& dist) {
    if (dist[a] < dist[b]) {
        swap(a, b);
    }
    for (int i = 0; i < 32; i++) {
        if ((dist[a] - dist[b]) >> i & 1) {
            a = prevs[i][a];
        }
    }

    if (a == b) {
        return a;
    }

    for (int i = 31; i >= 0; i--) {
        if (prevs[i][a] != prevs[i][b]) {
            a = prevs[i][a];
            b = prevs[i][b];
        }
    }

    return prevs[0][a];
}

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

    vector<vector<int>> prevs(32, vector<int>(n));
    vector<int> dist(n);
    dfs(0, -1, 0, g, prevs[0], dist);
    for (int i = 1; i < 32; i++) {
        for (int j = 0; j < n; j++) {
            if (prevs[i - 1][j] == -1) {
                prevs[i][j] = -1;
            }
            else {
                prevs[i][j] = prevs[i - 1][prevs[i - 1][j]];
            }
        }
    }

    vector<set<int>> rev_anses(n);
    vector<set<int>> self_anses(n);
    for (int i = 0; i < m - 1; i++) {
        int l = lca(a[i], a[i + 1], prevs, dist);
        rev_anses[l].insert(i);
    }
    for (int i = 0; i < m; i++) {
        self_anses[a[i]].insert(i);
    }

    for (int i = 0; i < q; i++) {
        int query_type;
        cin >> query_type;

        if (query_type == 1) {
            int pos, v;
            cin >> pos >> v;
            pos--;
            v--;
            if (pos != 0) {
                int l = lca(a[pos - 1], a[pos], prevs, dist);
                rev_anses[l].erase(pos - 1);
            }
            if (pos != m - 1) {
                int l = lca(a[pos], a[pos + 1], prevs, dist);
                rev_anses[l].erase(pos);
            }
            self_anses[a[pos]].erase(pos);
            a[pos] = v;
            if (pos != 0) {
                int l = lca(a[pos - 1], a[pos], prevs, dist);
                rev_anses[l].insert(pos - 1);
            }
            if (pos != m - 1) {
                int l = lca(a[pos], a[pos + 1], prevs, dist);
                rev_anses[l].insert(pos);
            }
            self_anses[a[pos]].insert(pos);
        } else {
            int l, r, v;
            cin >> l >> r >> v;
            l--;
            r--;
            v--;
            auto e = rev_anses[v].lower_bound(l);
            if (e == rev_anses[v].end() || *e >= r) {
                e = self_anses[v].lower_bound(l);
                if (e == self_anses[v].end() || *e > r) {
                    cout << -1 << " " << -1 << endl;
                } else {
                    int num = *e + 1;
                    cout << num << " " << num << endl;
                }
            } else {
                int num = *e + 1;
                cout << num << " " << (num + 1) << endl;
            }
        }
    }
}

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