删除数组的重复项 移动元素 实现strStr()（LeetCode第26 27 28题）

第26题：删除数组的重复项

class Solution:
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        
        i = 0
        
        while i < (len(nums)-1):
            if nums[i] == nums[i+1]:
                nums.remove(nums[i])
            else:
                i += 1
        return len(nums)

第27题：移除元素

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

第28题：实现strStr()
方法一：

class Solution:
    def strStr(self, haystack, needle):
        """
        :type haystack: str
        :type needle: str
        :rtype: int
        """
        
        if  len(needle)==0:
            return 0
        
        if (len(needle) > len(haystack)):
            return -1
        
        a = -1
        
        for i in range(len(haystack)):
            if haystack[i:i+len(needle)] == needle:
                a = i
                return a
        
        if a == -1:
            return -1

方法二：

if needle  not in haystack:
	return -1
return haystack.find(needle)