Q27 Remove Element

Given an array and a value, remove all instances of that value in-place and return the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

Example:

Given nums = [3,2,2,3], val = 3,

Your function should return length = 2, with the first two elements of nums being 2.

注意点：

空间复杂度要求为O(1)

解题思路：

遍历列表，如果和列表中元素和目标元素相同，则从列表中删除此元素。删除后列表长度会改变，注意不要越界。

Pyhton实现：

class Solution:
    def removeElement(self, nums, val):
        """
        :type nums: List[int]
        :type val: int
        :rtype: int
        """
        i = 0
        while i < len(nums):
            if nums[i] is val:
                del nums[i]
            else:
                i +=1
        return len(nums)        

a = [3,2,2,3]
b = Solution() 
print(b.removeElement(a,3))  # 2