15-110 PA4 Sample Solutions - Spring 2018

1.

from sieve import sieve
def factor(n):
    dividend = n
    primelist = sieve(n)
    possible_factor = primelist[0]
    primelist.remove(possible_factor)
    factors = []
    while dividend != 1:
        if (dividend % possible_factor == 0):
            factors.append(possible_factor)
            dividend = dividend // possible_factor
        else:
            possible_factor = primelist[0]
            primelist.remove(possible_factor)
    return factors

2.

def mean(numlist):
    n = len(numlist)
    sum = 0
    for x in numlist:
        sum = sum + 1/x
    result = n/sum
    return round(result, 3)

3.

def min_index(datalist):
# list is assumed to be non-empty
    min = datalist[0]
    min_index = 0
    for i in range(1, len(datalist)):
        if datalist[i] < min:            
            min = datalist[i]
            min_index = i
    return min_index     # instead of min

4.

def swap(datalist, i, j):
    temp = datalist[i]
    datalist[i] = datalist[j]
    datalist[j] = temp
    return None

from swap import swap
def bubble_sort(datalist):
    n = len(datalist)
    for scan in range(n-1):
        for index in range(0,n-1):
            if datalist[index] > datalist[index+1]:
                swap(datalist, index, index+1)
    return None