leetcode268

public class Solution
    {
        public int MissingNumber(int[] nums)
        {
            var list = nums.OrderBy(x => x).ToList();

            var preNum = 0;

            foreach (var l in list)
            {
                if (l != preNum)
                {
                    return preNum;
                }
                preNum++;
            }
            return preNum;
        }
    }

https://leetcode.com/problems/missing-number/#/description

 

补充一个python的实现：

class Solution:
    def missingNumber(self, nums):
        missing = len(nums)
        for i, num in enumerate(nums):
            missing ^= i ^ num
        return missing

不使用位运算特性：

class Solution:
    def missingNumber(self, nums: List[int]) -> int:
        nums.sort()
        prenum = 0
        for x in nums:
            if x != prenum:
                return prenum
            else:
                prenum += 1
        return prenum