Tunnels

import java.io.*;
import java.util.*;
 
public class C {
   public static void main(String[] args) throws IOException {
      BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
      PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
      (new C()).solve(in, out);
      out.close();
   }
 
   private int n, m;
   private ArrayList<ArrayList<Integer>> next;
   private int[] cc;
   private boolean[] vis;
 
   private void input(BufferedReader in, PrintWriter out) throws IOException {
      String[] tok = in.readLine().split(" ");
      n = Integer.parseInt(tok[0]);
      m = Integer.parseInt(tok[1]);
      next = new ArrayList<ArrayList<Integer>>(n+1);
      for(int i = 0; i <= n; i++) {
         next.add(new ArrayList<Integer>());
      }
      for(int i = 0; i < m; i++) {
         tok = in.readLine().split(" ");
         int u = Integer.parseInt(tok[0]);
         int v = Integer.parseInt(tok[1]);
         next.get(u).add(v);
      }
   }
 
   void dfs(int u) {
      if(cc[u] != -1) return;
      cc[u] = 1;
      for(Integer v : next.get(u)) {
         dfs(v);
         cc[u] += cc[v];
      }
   }
 
   int calc(int u) {
      if(vis[u]) return 0;
      vis[u] = true;
      int res = 0;
      for(Integer v : next.get(u)) {
         if(!vis[v]) {
            res += calc(v);
         }
      }
      return Integer.max(1, res);
   }
 
   public void solve(BufferedReader in, PrintWriter out) throws IOException {
      input(in, out);
      cc = new int[n + 1];
      vis = new boolean[n + 1];
      Arrays.fill(cc, -1);
      Arrays.fill(vis, false);
      for(int u = 1; u <= n; u++) {
         dfs(u);
      }
      Integer[] arr = new Integer[n];
      for(int i = 0; i < n; i++) {
         arr[i] = i+1;
      }
      Arrays.sort(arr,
         (u, v) -> cc[v] - cc[u]);
      int res = 0;
      for(int i = 0; i < n; i++) {
         res += calc(arr[i]);
      }
      out.println(res);
   }
}

Test 1

Group: 1

Verdict: WRONG ANSWER

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: WRONG ANSWER

Test 4

Group: 1

Verdict: WRONG ANSWER

Test 5

Group: 1

Verdict: WRONG ANSWER

Test 6

Group: 2

Verdict: WRONG ANSWER

Test 7

Group: 2

Verdict: WRONG ANSWER

Test 8

Group: 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER

Test 11

Group: 3

Verdict: WRONG ANSWER

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: WRONG ANSWER

Test 15

Group: 3

Verdict: WRONG ANSWER