[1. Two Sum] #lc0001

1_0807.java

public class Solution {
    public int[] twoSum(int[] nums, int target) {
        int[] result = new int[2];
        Map<Integer, Integer> visited = new HashMap<>();
        
        for (int i=0; i<nums.length; i++) {
            if (visited.containsKey(nums[i])) {
                result[0] = visited.get(nums[i]);
                result[1] = i;
                return result;
            }
            visited.put(target-nums[i], i);
        }
        return result;
    }
}