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November 11, 2017 01:11
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Different sorting methods in python
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def bubble_sort(L): | |
for i in range(len(L)-1, 0, -1): | |
for j in range(i): | |
if L[j] > L[j+1]: | |
temp = L[j] | |
L[j] = L[j+1] | |
L[j+1] = temp | |
def selection_sort(L): | |
for i in range(len(L)-1, 0, -1): | |
max_pos = 0 | |
for j in range(1, i+1): | |
if L[j] > L[max_pos]: | |
max_pos = j | |
temp = L[i] | |
L[i] = L[max_pos] | |
L[max_pos] = temp | |
def insertion_sort(L): | |
for i in range(1, len(L)): | |
current = L[i] | |
pos = i | |
while pos > 0 and L[pos-1] > current: | |
L[pos] = L[pos-1] | |
pos -= 1 | |
L[pos] = current | |
def merge_sort(L): | |
if len(L) > 1: | |
mid = len(L)//2 | |
left = L[:mid] | |
right = L[mid:] | |
merge_sort(left) | |
merge_sort(right) | |
i = 0 | |
j = 0 | |
k = 0 | |
while i < len(left) and j < len(right): | |
if left[i] < right[j]: | |
L[k] = left[i] | |
i += 1 | |
else: | |
L[k] = right[j] | |
j += 1 | |
k += 1 | |
while i < len(left): | |
L[k] = left[i] | |
i += 1 | |
k += 1 | |
while j < len(right): | |
L[k] = right[j] | |
j += 1 | |
k += 1 | |
def quick_sort(L): | |
quick_sort_helper(L, 0, len(L)-1) | |
def quick_sort_helper(L, first, last): | |
if first < last: | |
split = quick_sort_partition(L, first, last) | |
quick_sort_helper(L, first, split-1) | |
quick_sort_helper(L, split+1, last) | |
def quick_sort_partition(L, first, last): | |
pivot = L[first] | |
left = first+1 | |
right = last | |
done = False | |
while not done: | |
while left <= right and L[left] <= pivot: | |
left += 1 | |
while L[right] >= pivot and right >= left: | |
right -= 1 | |
if right < left: | |
done = True | |
else: | |
temp = L[left] | |
L[left] = L[right] | |
L[right] = temp | |
temp = L[first] | |
L[first] = L[right] | |
L[right] = temp | |
return right |
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