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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5. inline int power(int a, int b) {
  6.     int x = 1;
  7.     while (b) {
  8.         if (b & 1) x *= a;
  9.         a *= a;
  10.         b >>= 1;
  11.     }
  12.     return x;
  13. }
  14.  
  15.  
  16. const int M = 1000000007;
  17. const int N = 3e5+9;
  18. const int INF = 2e9+1;
  19. const int LINF = 2000000000000000001;
  20.  
  21. //_ ***************************** START Below *******************************
  22.  
  23.  
  24.  
  25. vector<int> a;
  26. int consistency(int n, int k) {
  27.  
  28. 	int ans = 0;
  29. 	unordered_map<int,int> freq;
  30. 	for(int i=0; i<n; i++){
  31. 		if(freq.count(k-a[i])){
  32. 			ans += freq[k-a[i]];
  33. 		}
  34. 		freq[a[i]]++;
  35. 	}
  36.  
  37. 	return ans;
  38. }
  39.  
  40.  
  41.  
  42.  
  43.  
  44.  
  45.  
  46.  
  47.  
  48.  
  49.  
  50.  
  51.  
  52.  
  53.  
  54. int practice(int n, int k) {
  55.  
  56. 	int ans = 0;
  57.  
  58.  
  59. 	return ans;	
  60. }
  61.  
  62. void solve() {
  63.  
  64.     int n, k;
  65.     cin >> n >> k;
  66.     a.resize(n);
  67.     for(int i=0; i<n; i++) cin >> a[i];
  68.  
  69.     // cout << consistency(n, k) << endl ;
  70.  
  71.     cout << consistency(n, k) << " -> " << practice(n, k) << endl ;
  72. }
  73.  
  74.  
  75.  
  76.  
  77.  
  78. int32_t main() {
  79.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  80.  
  81.     int t = 1;
  82.     while (t--) {
  83.         solve();
  84.     }
  85.  
  86.     return 0;
  87. }
Success #stdin #stdout 0.01s 5324KB
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https://ideone.com/5Gj0pX
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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