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.
注意點(diǎn)：
空間復(fù)雜度要求為O(1)
解題思路：
遍歷列表，如果和列表中元素和目標(biāo)元素相同，則從列表中刪除此元素厂庇。刪除后列表長(zhǎng)度會(huì)改變忧便，注意不要越界音诫。
Pyhton實(shí)現(xiàn)：
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
