hkasera

private boolean sumsToTarget(int[] arr, int k) { 
   Arrays.sort(arr); 
   int lhs = 0, rhs = arr.length - 1; 
   while (lhs < rhs) { 
     int sum = arr[lhs] + arr[rhs]; 
     if (sum == k) 
        return true; 
     else if (sum < k) 
        lhs++; 
     else rhs--; 

hkasera

private boolean sumsToTarget(int[] arr, int k) { 
   HashSet values = new HashSet(); 
   for (int i = 0; i < arr.length; i++) { 
       if (values.contains(k - A[i])) return true; 
       values.add(A[i]); 
   } 
   return false; 
}

hkasera

private boolean sumsToTarget(int[] arr, int k) { 
   Map<Integer, Integer> map = new HashMap<>();
    for (int i = 0; i < nums.length; i++) {
        int complement = target - nums[i];
        if (map.containsKey(complement)) {
            return new int[] { map.get(complement), i };
        }
        map.put(nums[i], i);
    }
    throw new IllegalArgumentException("No two sum solution");