Submission #502834

#	Time	Username	Problem	Language	Result	Execution time	Memory
502834		blue	Birthday gift (IZhO18_treearray)	C++17	100 / 100	1036 ms	84400 KiB

treearray

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;

using vi = vector<int>;
using vvi = vector<vi>;

const int lg = 18;
const int mx = 200'000;

vvi anc(1+mx, vi(1+lg, 1));

vi edge[1+mx];
vi depth(1+mx, 0);

void dfs(int u)
{
    for(int v: edge[u])
    {
        if(anc[u][0] == v) continue;
        depth[v] = 1 + depth[u];
        anc[v][0] = u;
        dfs(v);
    }
}

int lca(int u, int v)
{
    if(depth[u] > depth[v]) swap(u, v);

    for(int e = 0; e <= lg; e++)
        if((depth[v] - depth[u]) & (1 << e))
            v = anc[v][e];

    if(u == v) return u;

    for(int e = lg; e >= 0; e--)
    {
        if(anc[u][e] != anc[v][e])
        {
            u = anc[u][e];
            v = anc[v][e];
        }
    }

    return anc[u][0];
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n, m, q;
    cin >> n >> m >> q;

    for(int e = 1; e <= n-1; e++)
    {
        int u, v;
        cin >> u >> v;
        edge[u].push_back(v);
        edge[v].push_back(u);
    }

    dfs(1);

    for(int e = 1; e <= lg; e++)
        for(int u = 1; u <= n; u++)
            anc[u][e] = anc[ anc[u][e-1] ][e-1];


    vi a(1+m);
    for(int i = 1; i <= m; i++) cin >> a[i];

    vi L(m);
    for(int i = 1; i < m; i++) L[i] = lca(a[i], a[i+1]);

    // for(int i = 1; i < m; i++) cerr << i << " : " << L[i] << '\n';

    set<int> occ[1+n];
    for(int i = 1; i < m; i++)
        occ[L[i]].insert(i);

    set<int> occ_i[1+n];
    for(int i = 1; i <= m; i++) occ_i[a[i]].insert(i);

    // for(int v = 1; v <= n; v++)
    // {
    //     cerr << v << " : ";
    //     for(int o: occ_i[v]) cerr << o << ' ';
    //     cerr << '\n';
    // }

    for(int x = 1; x <= q; x++)
    {
        int t;
        cin >> t;

        if(t == 1)
        {
            int p, v;
            cin >> p >> v;

            if(p > 1)
                occ[L[p-1]].erase(p-1);
            if(p < m)
                occ[L[p]].erase(p);
            occ_i[a[p]].erase(p);

            a[p] = v;

            if(p > 1)
                L[p-1] = lca(a[p-1], a[p]);
            if(p < m)
                L[p] = lca(a[p], a[p+1]);

            if(p > 1)
                occ[L[p-1]].insert(p-1);
            if(p < m)
                occ[L[p]].insert(p);

            occ_i[a[p]].insert(p);

            // for(int i = 1; i <= m; i++) cerr << a[i] << ' ';
            // cerr << '\n';
            // for(int i = 1; i < m; i++) cerr << i << " : " << L[i] << '\n';
        }
        else
        {
            int l, r, v;
            cin >> l >> r >> v;

            auto z = occ[v].lower_bound(l);

            if(z == occ[v].end() || *z >= r)
            {
                // cerr << "#\n";
                // cerr << "oiv = ";
                // for(int o: occ_i[v]) cerr << o << ' ';
                // cerr << '\n';

                auto z2 = occ_i[v].lower_bound(l);


                if(z2 == occ_i[v].end() || *z2 > r) cout << "-1 -1\n";
                else cout << *z2 << ' ' << *z2 << '\n';
            }
            else cout << *z << ' ' << (*z)+1 << '\n';
        }
    }
}

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