Cod sursa(job #1318196)

Utilizator retrogradLucian Bicsi retrograd Data 15 ianuarie 2015 18:52:20
Problema Lowest Common Ancestor Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.68 kb
#include<fstream>


using namespace std;

typedef int var;

ifstream fin("lca.in");
ofstream fout("lca.out");

var *PARENT, *RANK;
var n;

inline var lca(var &a, var &b) {
    while(RANK[a] > RANK[b]) a = PARENT[a];
    while(RANK[b] < RANK[a]) b = PARENT[b];
    while(a != b) {a = PARENT[a]; b = PARENT[b];}
    return a;
}

int main() {

    var i, q;
    var a, b;

    fin>>n>>q;
    PARENT = new var[n+1];
    RANK = new var[n+1];
    PARENT[1] = RANK[1] = 0;
    for(i=2; i<=n; i++) {
        fin>>PARENT[i];
        RANK[i] = RANK[PARENT[i]] + 1;
    }

    while(q--) {
        fin>>a>>b;
        fout<<lca(a, b)<<'\n';
    }

    return 0;
}