931D - Peculiar apple-tree - CodeForces Solution

#include <fstream>
#include <vector>
#include <algorithm>
#include <stack>
#include <string>
#include <iostream>
using namespace std;
#define ll long long

const ll INF = 1e18;
vector<vector<int>> g;
vector<int> cnt;

void dfs(int v = 0, int h = 0) {
    if (cnt.size() <= h)
        cnt.push_back(1);
    else
        cnt[h]++;
    for (int u: g[v])
        dfs(u, h + 1);
}

int main() {
    int n; cin >> n;
    g.resize(n);
    for (int i = 0; i < n - 1; i++) {
        int x; cin >> x;
        g[x - 1].push_back(i + 1);
    }
    dfs();
    int ans = 0;
    for (int i: cnt) {
        ans += i % 2;
    }
    cout << ans << "\n";
    return 0;
}