Submission #1124365

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Source Code Expand

#include <algorithm>
#include <cmath>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
using namespace std;
typedef long long int lli;
int n;
vector<int> e[114514];
int dfs(int cur, int par)
{
    int len = e[cur].size();
    if (par != -1) {
        len--;
    }
    vector<int> s;
    for (auto to : e[cur]) {
        if (to == par)
            continue;
        s.push_back(dfs(to, cur));
    }
    sort(s.begin(), s.end());
    reverse(s.begin(), s.end());
    int ans = 0;
    rep(i, s.size())
    {
        int j = s[i];
        ans = max(ans, j + i + 1);
    }
    if (len == 0)
        ans = 0;
    // cout << "CUR= " << cur;
    // cout << "ANS= " << ans << endl;
    return ans;
}
int main()
{
    int b, c;
    cin >> n;
    rep(i, n - 1)
    {
        cin >> b;
        b--;
        c = i + 1;
        e[c].push_back(b);
        e[b].push_back(c);
    }
    cout << dfs(0, -1) << endl;
}

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