Submission #894449

#	Time	Username	Problem	Language	Result	Execution time	Memory
894449		12345678	Birthday gift (IZhO18_treearray)	C++17	100 / 100	991 ms	91916 KiB

treearray

#include <bits/stdc++.h>

using namespace std;

const int nx=2e5+5, kx=18;
int n, m, q, u, v, lvl[nx], pa[nx][kx], t, l, r, vl, x, a[nx];
vector<int> d[nx];
set<int> s[nx], o[nx];

void dfs(int u, int p)
{
    lvl[u]=lvl[p]+1;
    pa[u][0]=p;
    for (int i=1; i<kx; i++) pa[u][i]=pa[pa[u][i-1]][i-1];
    for (auto v:d[u]) if (v!=p) dfs(v, u);
}

int lca(int u, int v)
{
    if (lvl[u]>lvl[v]) swap(u, v);
    for (int i=kx-1; i>=0; i--) if (lvl[pa[v][i]]>=lvl[u]) v=pa[v][i];
    if (u==v) return u;
    for (int i=kx-1; i>=0; i--) if (pa[u][i]!=pa[v][i]) u=pa[u][i], v=pa[v][i];
    return pa[u][0];
}

void update(int idx)
{
    if (idx>1) s[lca(a[idx], a[idx-1])].insert(idx-1);
    if (idx<m) s[lca(a[idx], a[idx+1])].insert(idx);
    o[a[idx]].insert(idx);
}

void remove(int idx)
{
    if (idx>1) s[lca(a[idx], a[idx-1])].erase(idx-1);
    if (idx<m) s[lca(a[idx], a[idx+1])].erase(idx);
    o[a[idx]].erase(idx);
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m>>q;
    for (int i=0; i<n-1; i++) cin>>u>>v, d[u].push_back(v), d[v].push_back(u);
    dfs(1, 1);
    for (int i=1; i<=m; i++) cin>>a[i], update(i);
    while (q--)
    {
        cin>>t;
        if (t==1) 
        {
            cin>>x>>vl;
            remove(x);
            a[x]=vl;
            update(x);
        }
        else
        {
            cin>>l>>r>>vl;
            auto itr=o[vl].lower_bound(l), itr2=s[vl].lower_bound(l);
            if (itr!=o[vl].end()&&(*itr)<=r) cout<<*itr<<' '<<*itr<<'\n';
            else if (itr2!=s[vl].end()&&(*itr2)<r) cout<<*itr2<<' '<<*itr2+1<<'\n';
            else cout<<-1<<' '<<-1<<'\n';
        }
    }
}

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