Leetcode 540. Single Element in a Sorted Array

540. Single Element in a Sorted Array

アプローチ

Hashmap

class Solution {
    public int singleNonDuplicate(int[] nums) {
        if(nums == null || nums.length == 0){
            return 0;
        }
        HashMap<Integer, Integer> hashMap = new HashMap<>();
        for (int num : nums) {
            hashMap.put(num, hashMap.getOrDefault(num, -1) + 1);
        }

        return hashMap.keySet().stream().filter(key-> hashMap.get(key) == 0).findFirst().get();
    }
}