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  1.  
  2.  
  3.  
  4. #include <bits/stdc++.h>
  5. using namespace std;
  6.  
  7. int longestSuccessiveElements(vector<int>&a) {
  8.     int n = a.size();
  9.     if (n == 0) return 0;
  10.  
  11.     //sort the array:
  12.     sort(a.begin(), a.end());
  13.     int lastSmaller = INT_MIN;
  14.     int cnt = 0;
  15.     int longest = 1;
  16.  
  17.     //find longest sequence:
  18.     for (int i = 0; i < n; i++) {
  19.         if (a[i] - 1 == lastSmaller) {
  20.             //a[i] is the next element of the
  21.             //current sequence.
  22.             cnt += 1;
  23.             lastSmaller = a[i];
  24.         }
  25.         else if (a[i] != lastSmaller) {
  26.             cnt = 1;
  27.             lastSmaller = a[i];
  28.         }
  29.         longest = max(longest, cnt);
  30.     }
  31.     return longest;
  32.  
  33. }
  34.  
  35. int main()
  36. {
  37.     vector<int> a = {100, 200, 1, 2, 3, 4};
  38.     int ans = longestSuccessiveElements(a);
  39.     cout << "The longest consecutive sequence is " << ans << "\n";
  40.     return 0;
  41. }
  42.  
  43.  
Success #stdin #stdout 0.01s 5276KB
comments (?)
stdin 
Standard input is empty
stdout 
The longest consecutive sequence is 4
https://ideone.com/73o1iB
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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