问题描述:

image.png

输入：[4,3,2,7,8,2,3,1]
输出：[5,6]

代码示例一：

class Solution(object):
    def findDisappearedNumbers(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        list = [1]*len(nums)
        result = []
        for i in range(len(nums)):
            list[nums[i] - 1] = 0
        for i in range(len(nums)):
            if list[i] == 1:
                result.append(i+1)
        return result

代码示例二：不占用额外内存

class Solution(object):
    def findDisappearedNumbers(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        result = []
        for i in range(len(nums)):

            count = abs(nums[i])
            nums[count - 1] = - abs(nums[count - 1])

        for i in range(len(nums)):
            if nums[i] > 0:
                result.append(i+1)
        return result