Apartments

#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 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("apartments.txt", "r", stdin);

  int n, m, k;
  cin >> n >> m >> k;

  int desires[n] = {};
  REP(i, 0, n) { cin >> desires[i]; }
  sort(desires, desires + n);

  int apartments[m] = {};
  REP(i, 0, m) { cin >> apartments[i]; }
  sort(apartments, apartments + m);

  int i = 0, j = 0;
  int res = 0;
  while (i < n && j < m) {
    bool too_small = apartments[j] < desires[i] - k;
    bool too_big = apartments[j] > desires[i] + k;
    if (!too_small && !too_big) {
      i++;
      j++;
      res++;
    } else if (too_small) {
      j++;
    } else {
      i++;
    }
  }

  cout << res << 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

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED