Binge watching

#define F first
#define S second
#define PB push_back
#define MP make_pair
#define REP(i, a, b) for (int i = a; i < b; ++i)
#define BR "\n"

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef pair<int, int> pi;

void dfs(int s, vi adj[], bool vis[]) {
  if (vis[s]) {
    return;
  }
  vis[s] = true;
  // process s
  for (auto u : adj[s]) {
    dfs(u, adj, vis);
  }
}

int main() {
  // uncomment if io is a bottleneck
  // ios::sync_with_stdio(0);
  // cin.tie(0);

  // uncomment to read cin from a file
  // freopen("b.txt", "r", stdin);

  int n;
  cin >> n;
  vector<pi> arr;
  REP(i, 0, n) {
    int a, b;
    cin >> a >> b;
    arr.PB(MP(b, a));
  }

  sort(arr.begin(), arr.end());

  // REP(i, 0, n) { cout << arr[i].F << " " << arr[i].S << BR; }

  vector<pi> ans;
  pi prev;

  REP(i, 0, n) {
    auto time = arr[i];
    if (time.S < prev.F) {
      continue;
    }

    ans.push_back(time);

    prev = time;
  }

  cout << ans.size() << BR;

  return EXIT_SUCCESS;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED