partition

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 len(nums) == 0:
            return 0
        j = len(nums)-1
        i = 0
        while i <=j and nums[i]<k:
            i+=1
        if i > j:
            return len(nums)
        while nums[j] >= k:
            if j > i:
                j -= 1
            else:
                break
        if j == i:
            return j
        while i<j:
            if nums[i]>=k:
                while nums[j]>=k:
                    if j > i:
                        j-=1
                    else:
                        return j
                temp = nums[j]
                nums[j]=nums[i]
                nums[i]=temp
            i+=1
        return j