Submission #89721

#	Time	Username	Problem	Language	Result	Execution time	Memory
89721		Abelyan	Birthday gift (IZhO18_treearray)	C++14	100 / 100	1678 ms	107212 KiB

treearray

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

const int N=200005;
const int LG=log2(N)+3;

vector<int> g[N];
int anc[N][LG];
int n,m,q,l;
int in[N],out[N],timer;

void dfs(int v,int par=0){
    in[v]=timer++;
    anc[v][0]=par;
    for (int i=1;i<=l;i++){
        anc[v][i]=anc[anc[v][i-1]][i-1];
    }
    for (auto to:g[v]){
        if (to==par)continue;
        dfs(to,v);
    }
    out[v]=timer++;
}

bool is_anc(int a,int b){
    if (b==0 || a==b)return true;
    if (in[a]>in[b] && in[a]<out[b])return true;
    return false;
}

int lca(int a,int b){
    if (is_anc(a,b)) return b;
    if (is_anc(b,a)) return a;
    for (int i=l;i>=0;i--)
        if (!is_anc(b,anc[a][i]))
            a=anc[a][i];
    return anc[a][0];
}

int a[N];
set<int> sl[N],pr[N];
set<int>::iterator it;
int main(){
    ios_base::sync_with_stdio(false);
    //freopen("input.txt","r",stdin);
    cin>>n>>m>>q;
    l=0;
    while ((1<<l)<=n)l++;
    for (int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1);
    for (int i=1;i<=m;i++){
        cin>>a[i];
        sl[a[i]].insert(i);
        if (i!=1){
            //cout<<lca(a[i],a[i-1])<<" "<<i-1<<endl;
            pr[lca(a[i],a[i-1])].insert(i-1);
            //cout<<lca(a[i],a[i-1])<<" "<<i-1<<endl;
        }
    }
    for (int i=0;i<q;i++){
        int type;
        cin>>type;
        if (type==1){
            int ind,val;
            cin>>ind>>val;
            sl[a[ind]].erase(sl[a[ind]].find(ind));
            sl[val].insert(ind);
            if (ind!=1){
                int oldval=lca(a[ind],a[ind-1]),newval=lca(val,a[ind-1]);
                pr[oldval].erase(pr[oldval].find(ind-1));
                pr[newval].insert(ind-1);
            }
            if (ind!=m){
                int oldval=lca(a[ind],a[ind+1]),newval=lca(val,a[ind+1]);
                //cout<<oldval<<" "<<ind<<endl;
                pr[oldval].erase(pr[oldval].find(ind));
                pr[newval].insert(ind);
            }
            a[ind]=val;
        }
        else{
            int l,r,v;
            cin>>l>>r>>v;
            if (sl[v].size()){
                it=sl[v].lower_bound(l);
                if (it!=sl[v].end() && *it<=r){
                    cout<<*it<<" "<<*it<<endl;
                    continue;
                }
            }
            if (pr[v].size()){
                it=pr[v].lower_bound(l);
                if (it!=pr[v].end() && *it<r){
                    //cout<<*it<<endl;
                    cout<<*it<<" "<<*it+1<<endl;
                    continue;
                }
            }
            cout<<-1<<" "<<-1<<endl;
        }
    }
    return 0;
}

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