LC#1

 1 class Solution {
 2     public int[] twoSum(int[] nums, int target) {
 3         Map<Integer,Integer> map=new HashMap<>();
 4         for(int i=0;i<nums.length;i++){
 5             int x=target-nums[i];
 6             if(map.containsKey(x)){
 7                 return new int[] {map.get(x),i};
 8             }
 9             map.put(nums[i],i);
10         }
11          throw new IllegalArgumentException("No two sum solution");
12     }
13 }
14     }
15 }