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  1.  
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4. struct range {
  5. 	int start;
  6. 	int end;
  7. 	range(int s, int e) {start=s; end=e;}
  8. };
  9.  
  10. void find_longest_consecutive_numbers(vector<int>& N)
  11. {
  12. 	unordered_map<int,range> hash;
  13. 	unordered_map<int,range>::iterator left, right;
  14.  
  15. 	range max_range(0,0);
  16. 	int max_length=0;
  17.  
  18. 	for(int i=0; i<N.size(); i++) {		
  19. 		range r(N[i],N[i]);
  20.  
  21. 		left = hash.find(N[i]-1);
  22. 		right = hash.find(N[i]+1);
  23.  
  24.         // update range r
  25. 		if( left!=hash.end() ) 
  26. 			r.start = left->second.start;
  27. 		if( right!=hash.end() )
  28. 			r.end = right->second.end;
  29.  
  30. 		// update hash table
  31. 		if( left!=hash.end() ) 
  32. 			left->second.end = r.end;
  33. 		if( right!=hash.end() )
  34. 			right->second.start = r.start;
  35.  
  36. 		// insert range r
  37. 		hash.insert(make_pair(N[i],r));
  38.  
  39. 		// check if this range was the longest
  40. 		if( r.end-r.start+1 > max_length ) {
  41. 			max_length = r.end-r.start+1;
  42. 			max_range.start = r.start;
  43. 			max_range.end = r.end;
  44. 		}
  45. 	}
  46.  
  47. 	printf("longest range = %d : %d\n", max_range.start, max_range.end);
  48. }
  49. int main(){
  50.  vector<int> arr={1,6,10,4,7,9,5} ;
  51.  find_longest_consecutive_numbers(arr);
  52.  return 0;
  53. }
  54.  
Success #stdin #stdout 0s 16064KB
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Standard input is empty
stdout
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longest range = 4 : 7
https://ideone.com/Bvenfk
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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