Cod sursa(job #3278473)

Utilizator Bianca2507Negret Bianca Bianca2507 Data 19 februarie 2025 21:56:49
Problema Lowest Common Ancestor Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.79 kb
#include <fstream>
#include <vector>
using namespace std;
ifstream cin("lca.in");
ofstream cout("lca.out");

int n,m,nivel[100005],tata[100005];
vector<int>l[100005];
void dfs(int nod,int niv)
{
    nivel[nod]=niv;
    for(int i=0;i<l[nod].size();i++)
    {
        int vecin=l[nod][i];
        dfs(vecin,niv+1);
    }
}
int lca(int x,int y)
{
    if(nivel[x]<nivel[y])
        swap(x,y);
    while(nivel[x]>nivel[y])
        x=tata[x];
    while(x!=y)
    {
        x=tata[x];
        y=tata[y];
    }
    return x;
}
int main()
{
    cin>>n>>m;
    for(int i=2;i<=n;i++)
    {
        cin>>tata[i];
        l[tata[i]].push_back(i);
    }
    dfs(1,1);
    while(m--)
    {
        int x,y;
        cin>>x>>y;
        cout<<lca(x,y)<<'\n';
    }
    return 0;
}