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Counting-sort.py
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Counting-sort.py
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#python program for counting sort (updated)
n=int(input("please give the number of elements\n"))
print("okey now plase enter n numbers seperated by spaces")
tlist=list(map(int,input().split()))
k = max(tlist)
n = len(tlist)
def counting_sort(tlist, k, n):
""" Counting sort algo with sort in place.
Args:
tlist: target list to sort
k: max value assume known before hand
n: the length of the given list
map info to index of the count list.
Adv:
The count (after cum sum) will hold the actual position of the element in sorted order
Using the above,
"""
# Create a count list and using the index to map to the integer in tlist.
count_list = [0]*(k+1)
# iterate the tgt_list to put into count list
for i in range(0,n):
count_list[tlist[i]] += 1
# Modify count list such that each index of count list is the combined sum of the previous counts
# each index indicate the actual position (or sequence) in the output sequence.
for i in range(1,k+1):
count_list[i] = count_list[i] + count_list[i-1]
flist = [0]*(n)
for i in range(n-1,-1,-1):
count_list[tlist[i]] =count_list[tlist[i]]-1
flist[count_list[tlist[i]]]=(tlist[i])
return flist
flist = counting_sort(tlist, k, n)
print(flist)