Question

In Java, write a program that given an array A[1...n] and a value S finds 0 < i < j < n such that A[i] + A[j] = S

Answer 1

The snapshot of the output

// Java implementation using Hashing
import java.io.*;
import java.util.HashSet;

class PairSum {
   static void printpairs(int arr[], int sum)
   {
       HashSet<Integer> s = new HashSet<Integer>();
       for (int i = 0; i < arr.length; ++i) {
           int temp = sum - arr[i];

           // checking for condition
           if (s.contains(temp)) {
               System.out.println("Pair with given sum " + sum + " is (" + arr[i] + ", " + temp + ")");
           }
           s.add(arr[i]);
       }
   }

   // Main to test the above function
   public static void main(String[] args)
   {
       int A[] = { 1, 4, 45, 6, 10, 8 };
       int n = 16;
       printpairs(A, n);
   }
}