Cod sursa(job #2287277)

Utilizator Ioana_AndreeaCristescu Ioana Ioana_Andreea Data 21 noiembrie 2018 18:38:07
Problema Lowest Common Ancestor Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 kb
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("lca.in");
ofstream fout("lca.out");
const int NMax = 100000;
vector <int> G[NMax + 5];
int N,M;
int TT[NMax + 5],Level[NMax + 5];
void Read()
{
    fin >> N >> M;
    for(int i = 2; i <= N; ++i)
    {
        fin >> TT[i];
        G[TT[i]].push_back(i);
    }
}

void DFS(int Nod)
{
    for(int i = 0; i < (int)G[Nod].size(); ++i)
    {
        int Vecin = G[Nod][i];
        Level[Vecin] = Level[Nod] + 1;
        DFS(Vecin);
    }
}

int LCA(int x, int y)
{
    if(Level[x] < Level[y])
        swap(x,y);
    while(Level[x] != Level[y])
        x = TT [x];
    while(x != y)
    {
        x = TT[x];
        y = TT[y];
    }
    return x;
}

void SolveandPrint()
{
    DFS(1);
    while(M--)
    {
        int x,y;
        fin >> x >> y;
        fout << LCA(x,y)<< "\n";
    }
}

int main()
{
    Read();
    SolveandPrint();
    return 0;
}