1121A - Technogoblet of Fire - CodeForces Solution

/*
ॐ त्र्यम्बकं यजामहे सुगन्धिं पुष्टिवर्धनम् ।
उर्वारुकमिव बन्धनान् मृत्योर्मुक्षीय मामृतात् ॥ */

#include <bits/stdc++.h>
using namespace std;
#define int long long

signed main()
{
    int n, m, k;
    cin >> n >> m >> k;
    int power[n], school[n];
    int select[k];
    unordered_map<int, int> um;
    for (int i = 0; i < n; i++)
    {
        cin >> power[i];
    }
    for (int i = 0; i < n; i++)
    {
        cin >> school[i];
        if (um[school[i]] < power[i])
        {
            um[school[i]] = power[i];
        }
    }
    int ans = 0;
    for (int i = 0; i < k; i++)
    {
        cin >> select[i];
        if (power[select[i] - 1] != um[school[select[i] - 1]])
        {
            ans++;
        }
    }
    cout << ans;

    return 0;
}