def removeDuplicates(self, nums):  
    # write your code here  
    if nums == []:  
        return 0  
    index,count = 0, 1  
    for i in range(1, len(nums)):  
        if nums[index] == nums[i] and count < 2:  
            index += 1  
            count += 1  
            nums[index] = nums[i]  
        
 
if nums[index] != nums[i]:  
            index += 1  
            count = 1  
            nums[index] = nums[i]  
    return index+1  

101. 刪除排序數組中的重復數字 II