fork download
copy 
  1. #include <bits/stdc++.h>
  2. #define ll long long
  3. #define pb push_back
  4. #define pll pair<ll, ll>
  5. #define el "\n"
  6. using namespace std;
  7. const ll MOD = 1e9 + 7;
  8. const ll maxN = 1e5 + 5;
  9. void INIT() {
  10.     ios::sync_with_stdio(0); cin.tie(0);
  11.     //freopen("SOCAP.INP", "r", stdin); 
  12.     //freopen("SOCAP.OUT", "w", stdout); 
  13. }
  14. vector<ll> a(maxN);
  15. int main() {
  16.     INIT();
  17.     ll n, x, ans = 0; cin >> n >> x;
  18.     for(int i = 1; i <= n; i++) cin >> a[i];
  19.     sort(a.begin()+1, a.begin()+n+1);
  20.     for(int i = 1; i < n; i++) {
  21.     	if (x<a[i]) continue;
  22.         ll y = x-a[i];
  23.         if (binary_search(a.begin()+i+1, a.begin()+n+1,y)) ans++;
  24.     }
  25.     cout << ans << el;
  26.     return 0;
  27. }
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin
copy 
8 15
5 12 6 10 9 1 2 3
stdout
copy 
3
https://ideone.com/Y3CYHb
language:
C++14 (gcc 8.3)
created:
21 hours ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!