1+ class TwoSum {
2+ 3+ /*
4+ * Time Complexity O(n)
5+ * Space Complexity O(n)
6+ *
7+ * Step 1 : Declare a Map of Integers which will be used for comparison
8+ * Step 2 : Run through the array with index
9+ * Step 3 : Substract the current element from target sum and store it
10+ * Step 4 : Check if the complement present in the map
11+ * Step 5 : If present then create and return an array of Integers with the index
12+ * of the current element and fetched value from map with the complement key
13+ * Step 6 : Otherwise set the map with current element as key and current index
14+ * as value
15+ * Step 7 : Return an empty array by default
16+ * */
17+ 18+ fun twoSum (nums : IntArray , target : Int ): IntArray {
19+ val seen = mutableMapOf<Int , Int >()
20+ 21+ // using array with index as index and value both are required for computation
22+ for ((index, element) in nums.withIndex()){
23+ val complement = target - element
24+ if ( complement in seen )
25+ return intArrayOf(seen.get(complement)!! , index)
26+ // setting the map with the current index
27+ seen[element] = index
28+ }
29+ return intArrayOf()
30+ }
31+ }
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