Partition Array – Python 3 (Week 18 – 11)

class Solution:
    """
    @param nums: The integer array you should partition
    @param k: An integer
    @return: The index after partition
    """
    def partitionArray(self, nums, k):
        # write your code here
        if not nums or not k:
            return 0
            
        left, right = 0, len(nums)
        
        while left <= right:
            while left <= right and nums[left] < k:
                left += 1
            while left <= right and nums[right] >= k:
                right -= 1
            if left <= right:
                nums[left], nums[right] = nums[right], nums[left]
                left += 1
                right -= 1
                
        return left