0001 Two Sum

0001 Two Sum.java

class Solution {
    public int[] twoSum(int[] nums, int target) {
        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 Answer");
    }
}