CSES :: Tree Algorithms :: Subordinates

Problem : Please find the problem here.

Explanation : Company's employee hierarchy can be intutively mapped as tree structure and for each employee, the subordinate count is the sum of subordinates count of all their direct subordinates.

Code : Used DFS to traverse the tree starting from the node 0. This calculates the subordinates for each employee by summing counts recursively.

Time Complexity : O(N), where n is the number of nodes in the tree.

#include <bits/stdc++.h>

using namespace std;

void DFS(int node, int parent, vector<int> &subordinates, vector<vector<int>> &adj) {
    subordinates[node] = 1;

    for (int next : adj[node]) {
        DFS(next, node, subordinates, adj);
        subordinates[node] += subordinates[next];
    }
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, x;
    cin >> n;
    vector<vector<int>> adj(n);
    vector<int> subordinates(n);

    // relation data for employee 1 to n; 0th is boss.
    for (int i = 1; i < n; i++) {
        cin >> x; x--;
        adj[x].emplace_back(i);
    }

    DFS(0, -1, subordinates, adj);

    for (int c : subordinates) {
        cout << c-1 << ' ';
    }
    return 0;
}