Bubble sort a list of integers for a number of iterations

Question

I wrote a program for this problem, but it stopped because it took too much time. Any tips?

The Problem: Bubble sort is the simplest algorithm for elements sorting. At each iteration we sequentially compare values of subsequent elements and swap them if necessary.

Your job is to write a program which finds a state of a given list of positive integer numbers after applying a given count of bubble sort iterations

Input Sample: Each line contains a space-separated list of positive integers and ends with a number of iterations, separated by vertical line ‘|’. Example:

48 51 5 61 18 | 2

Output Sample:

5 48 18 51 61

Explanation:

Iteration 1: 48 5 51 18 61

Iteration 2: 5 48 18 51 61

My code:

def bubsort(num, iters):
    itered = 1
    while itered != iters + 1:
        nums = sorting(num)
        itered += 1
    print ' '.join(num)

def sorting(num):
    for i in xrange(len(num) - 1):
        challenger = int(num[i])
        opponent = int(num[i + 1])
        if challenger > opponent:
            num[i], num[i + 1] = num[i + 1], num[i]
    return num

test = raw_input()
whole = test.strip().split(' | ')
num = whole[0].split()
iters = int(whole[1])
bubsort(num, iters)

Answer 1

Three improvements:

• Use the for loop idiom instead of a counter and use _ for variables you don't use.

• return the result, don't print it, you should separate processing and output.

• Use nums, not num because you should sort multiple numbers, a plural is a more sensible choice.

def bubsort(nums, iters):
    for _ in xrange(iters):
        nums = sorting(nums)
    return nums

Answer 2

In addition to what Caridorc said, move the integer casting outside your sorting function (this will also make your code a tiny bit more efficient):

def sorting(nums):
    for i in xrange(len(nums) - 1):
        if nums[i] > nums[i + 1]:
            nums[i], nums[i + 1] = nums[i + 1], nums[i]
    return nums

And later use a list comprehension to convert the strings to numbers:

test = raw_input()
whole = test.strip().split(' | ')
num = [int(x) for x in whole[0].split()]
iters = int(whole[1])
bubsort(num, iters)

It should also be noted that .strip() isn't really needed, since int(" 2 ") == 2, but it doesn't hurt to have it there, either.