Submission #978890

#	Time	Username	Problem	Language	Result	Execution time	Memory
978890		irmuun	Birthday gift (IZhO18_treearray)	C++17	30 / 100	4040 ms	7204 KiB

treearray

#include<bits/stdc++.h>

using namespace std;

#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()

const int N=2e5+5;

int n,m,q,a[N],par[N][20],dep[N];
vector<int>adj[N];
void dfs(int x,int p){
    par[x][0]=p;
    for(int y:adj[x]){
        if(y!=p){
            dep[y]=dep[x]+1;
            dfs(y,x);
        }
    }
}
int up(int x,int d){
    for(int i=19;i>=0;i--){
        if(d&(1<<i)){
            x=par[x][i];
        }
    }
    return x;
}
int lca(int x,int y){
    if(dep[x]<dep[y]) swap(x,y);
    x=up(x,dep[x]-dep[y]);
    for(int i=19;i>=0;i--){
        if(par[x][i]!=par[y][i]){
            x=par[x][i];
            y=par[y][i];
        }
    }
    if(x!=y) x=par[x][0];
    return x;
}

void ask(int l,int r,int u){
    for(int x=l;x<=r;x++){
        int cur=a[x];
        for(int y=x;y<=r;y++){
            cur=lca(cur,a[y]);
            if(cur==u){
                cout<<x<<' '<<y<<"\n";
                return;
            }
            if(dep[cur]<dep[u]) break;
        }
    }
    cout<<"-1 -1\n";
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    cin>>n>>m>>q;
    for(int i=1;i<n;i++){
        int u,v;
        cin>>u>>v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    for(int i=1;i<=m;i++){
        cin>>a[i];
    }
    dep[1]=0;
    dfs(1,1);
    for(int j=1;j<20;j++){
        for(int i=1;i<=n;i++){
            par[i][j]=par[par[i][j-1]][j-1];
        }
    }
    while(q--){
        int t;
        cin>>t;
        if(t==1){
            int pos,v;
            cin>>pos>>v;
            a[pos]=v;
        }
        else{
            int l,r,u;
            cin>>l>>r>>u;
            ask(l,r,u);
        }
    }
}

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