Question

How to find the pair in array whose sum is nearest to a number N in a sorted array in C++

Answer 1

#include <iostream>
#include <climits>

int main()
{
  int arr[]= {3, 5, 7, 12, 18, 20, 23, 27, 30};
  int size = sizeof(arr)/sizeof(arr[0]);
   
  int N = 22;
 
  int left = 0, right = size - 1, sum = 0;
  int nearest = INT_MAX, nearest_sum; 
  int paira, pairb;
   
  while(left < right) {
    sum = arr[left] + arr[right];
     
    if (abs(N - sum) < nearest) {
      nearest = abs(N -sum);
      nearest_sum = sum;
      paira = arr[left];
      pairb = arr[right];
    }
     
    if (sum > N)
      right--;
    else if (sum <= N)
      left++;
  }
  std::cout << nearest_sum << "\n";
  std::cout << paira << " " << pairb;
}
 
 
 
 
/*
run:
 
23
3 20
 
*/

 

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