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  1. #include <iostream>
  2. #include<bits/stdc++.h>
  3. using namespace std;
  4. using ll = long long;
  5. #define fo(i,start,end) for(int i=start;i<end;i++)
  6.  
  7. vector<pair<int,int>> FindOptimalPairs(vector<int>&arr,int k){
  8. 	vector<pair<int,int>>result;
  9. 	// arrr = {1,5,3,4,2}, k = 2
  10. 	unordered_map<int,int>mp; //element -> index
  11. 	fo(j,0,5){
  12. 		int a1 = k + arr[j]; // 2 + 3 = 5
  13. 		int a2 = arr[j] - k; // 3 - 2 = 1
  14. 		if(mp.find(a1) != mp.end()){
  15. 			result.push_back({mp[a1],j});
  16. 		}
  17. 		 if(mp.find(a2) != mp.end()){
  18. 			result.push_back({mp[a2],j});
  19. 		}
  20. 		mp[arr[j]] = j;
  21. 	}
  22. 	//for loop ends here
  23. 	return result;
  24. }
  25.  
  26.  
  27. int main() {
  28. 	// your code goes here
  29. 	vector<int>arr = {1,5,3,4,2};
  30. 	ll k = 2;
  31. 	vector<pair<int,int>>ans = FindOptimalPairs(arr,k);
  32. 	cout<<"Pairs are:"<<endl;
  33. 	for(pair<int,int>& it:ans){
  34. 		int fp = it.first;
  35. 		int sp = it.second;
  36. 		cout<<"{"<<fp+1<<","<<sp+1<<"},"<<endl; //one based indexing
  37. 	}
  38. 	return 0;
  39. }
Success #stdin #stdout 0.01s 5288KB
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Standard input is empty
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Pairs are:
{2,3},
{1,3},
{4,5},
https://ideone.com/6GCPcc
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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