剑指 Offer 56 - II. 数组中数字出现的次数 II(java & python)

遍历了 也没什么不好～

java：

class Solution {
    public int singleNumber(int[] nums) {
        int res = 0;
        HashMap hash = new HashMap<>();
        for(int i = 0; i < nums.length; i++){
            hash.put(nums[i], hash.getOrDefault(nums[i],0) + 1);
        }
        for(int num : nums){
            if(hash.get(num) == 1){
                res = num;
            }
        }
        return res;
    }
}

python：

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        dic = {}
        for ch in nums:
            if ch not in dic.keys():
                dic[ch] = 1
            else:
                dic[ch] += 1
        for ch in dic.keys():
            if dic[ch] == 1:
                return ch