Move Zeroes

Unit 1 Session B

U-nderstand

Understand what the interviewer is asking for by using test cases and questions about the problem.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: First, move all non-zero elements to the beginning of the list, preserving their order. Then fill the remaining space with zeroes.

1) Create a new list to store the result
2) Loop through the numbers and add each non-zero number into the results list
3) Count how many zeroes were in the original list
4) Add that many zeroes to the end of the results list

I-mplement

def move_zeroes(nums):
	result = []
	for num in nums:
		if num != 0:
			result.append(num)
		
	zero_count = nums.count(0)
	for num in range(1, zero_count + 1):
		result.append(0)

    return result

Alternatively, you can deduce the number of zeroes by subtracting the length of the "non-zeroes" list from the length of the original list:

def move_zeroes(nums):
	result = []
	for num in nums:
		if num != 0:
			result.append(num)
		
	zero_count = len(nums) - len(result)
	for num in range(1, zero_count + 1):
		result.append(0)

    return result