HackerEarth Big P and Punishment problem solution

In this HackerEarth Big P and Punishment problem solution Big P has become a Physical Education teacher at Hack International School.

Today, the students of class XII have been very undisciplined and he decides to punish them all.

He makes all of the N student (numbered 1 to N ) to stand in a line and asks them to sit down on their knees.

Students know that Big P is a very cruel and sadistic person and students start to sit down themselves when they see a friend sit down.

However, there are always some students who do not follow the trend. Now when Big P sees that happen , he slaps that student and makes him sit down. The same process as above is followed and is stopped when any - one student in the line refuses to sit down by himself.

Given the students that Big P slaps to make them sit down , you need to tell the total no. of students who sat down in that line.

HackerEarth Big P and Punishment problem solution.

#include <algorithm>
#include <iostream>
#include <iterator>
#include <sstream>
#include <fstream>
#include <cassert>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cstdio>
#include <vector>
#include <cmath>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <set>
#define D(x) cout << #x " is " << x << endl
using namespace std;
const int N = 10009;

vector<int> g[N];
bool sat[N];
int ans;

void sit(int u){
  if (sat[u]) return;

  ans++;
  sat[u] = true;

  for (int i=0; i<g[u].size(); ++i) sit(g[u][i]);
}

int main()
{
    
  int c;
  for (cin >> c; c--; cout << ans << endl)
  {
    int n, m, l; 
    cin>>n>>m>>l;
    for (int i=0; i<=n;i++)
    {
      g[i].clear();
      sat[i] = false;
    }
    while(m--)
    {
      int u, v;
      cin >> u >> v;
      g[u].push_back(v);
    }

    ans = 0;
    while (l--)
    {
      int u;
      cin >> u;
      sit(u);
    }
  }

  return 0;
}

Second solution

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
vector<vector<int> > adj;

void dfs(int idx,bool *visited){

  visited[idx]=1;

  for(vector<int> :: iterator it=adj[idx].begin();it!=adj[idx].end();++it)
  {
     if(visited[*it]==false)
      dfs(*it,visited);
  }
}
int main(){

 int t;
 cin>>t;
 while(t--){
  int n,f,s;
  cin>>n>>f>>s;
  adj.resize(n);
  for(int i=0;i<f;i++){
   int a,b;
   cin>>a>>b;
   adj[a-1].pb(b-1);
  }
  bool visited[n];
  memset(visited,0,sizeof(visited));
  for(int i=0;i<s;i++){
   int idx;
   cin>>idx;
   dfs(idx,visited);
  }
  int count=0;
  for(int i=0;i<n;i++) if(visited[i]) count++;

  cout<<count<<endl;
 }
 return 0;
}