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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. #define print(a)         for(auto x : a) cout << x << " "; cout << endl
  6.  
  7.  
  8. const int M = 1000000007;
  9. const int N = 3e5+9;
  10. const int INF = 2e9+1;
  11. const int LINF = 2000000000000000001;
  12.  
  13. inline int power(int a, int b, int mod=M) {
  14.     int x = 1;
  15.     a %= mod;
  16.     while (b) {
  17.         if (b & 1) x = (x * a) % mod; 
  18.         a = (a * a) % mod;
  19.         b >>= 1;
  20.     }
  21.     return x;
  22. }
  23.  
  24.  
  25. //_ ***************************** START Below *******************************
  26.  
  27. // 7 20
  28. // 1 2 2 3 4 4 6
  29.  
  30.  
  31. vector<int> a;
  32.  
  33. //* no. of pairs with dist <= x
  34.  
  35. //* x = 2
  36.  
  37. // ( 2    4 )   5    5   6   7   
  38. //   2  ( 4     5 )  5   6   7   
  39. //   2  ( 4     5    5 ) 6   7   
  40. //   2  ( 4     5    5   6)  7   
  41. //   2    4   ( 5    5   6   7 )  
  42.  
  43.  
  44. int count(int n, int x){
  45. 	int ct = 0;
  46. 	int s = 0, e = 0;
  47.  
  48. 	while(e<n && s<n-1){
  49. 		if(s==e) e++;
  50. 		if(a[e]-a[s] <= x){
  51. 			e++;
  52. 			ct += e-s;
  53. 		}
  54. 		else{
  55. 			s++;
  56. 		}
  57.  
  58. 	}
  59.  
  60. 	return ct;
  61. }
  62.  
  63. int consistency(int n, int k){
  64.  
  65. 	sort(begin(a), end(a));
  66.  
  67. 	int s = 0, e = a[n-1]-a[0];
  68.  
  69. 	while(s<e){
  70. 		int mid = s + (e-s)/2;
  71. 		if(count(n, mid) >= k){
  72. 			e = mid;
  73. 		}
  74. 		else s = mid+1;
  75. 	}
  76.  
  77. 	return e;
  78.  
  79. }
  80.  
  81.  
  82.  
  83.  
  84.  
  85.  
  86.  
  87.  
  88.  
  89.  
  90.  
  91.  
  92.  
  93.  
  94.  
  95. int practice(int n, int k){
  96.  
  97.  
  98.     return 0;
  99. }
  100.  
  101.  
  102.  
  103.  
  104.  
  105. void solve() {
  106.  
  107.     int n, k;
  108.     cin>> n >> k;
  109.  
  110.     a.resize(n);
  111.     for(int i=0; i<n; i++) cin >> a[i];
  112.  
  113.     cout << consistency(n, k) << endl;
  114.  
  115.  
  116. }
  117.  
  118.  
  119.  
  120.  
  121.  
  122. int32_t main() {
  123.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  124.  
  125.     int t = 1;
  126.     // cin >> t;
  127.     while (t--) {
  128.         solve();
  129.     }
  130.  
  131.     return 0;
  132. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
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7 20
1 2 2 3 4 4 5
stdout
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2
https://ideone.com/eZ8VTH
language:
C++14 (gcc 8.3)
created:
18 hours ago
visibility:
public

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