import sys
def mergesort_2ndstep(l, r):
len_l = len(l)
len_r = len(r)
# initializing a list of length zero
sorted_array = []
i,j = 0,0
while i < len_l:
num1 = l[i]
for x in range(j,len_r):
num2 = r[x]
if num2 < num1 :
sorted_array.append(num2)
j += 1
sorted_array.append(num1)
i += 1
if len(sorted_array) != len_l + len_r:
# Checking extreme conditions
sorted_array[i+j:] = r[j:]
return sorted_array
def mergesort_1ststep(L,start,stop):
# a list can be divided into two
# if length of list is atleast two
if stop - start > 1:
l = mergesort_1ststep(L,start,start + (stop-start)//2)
r = mergesort_1ststep(L,start + (stop-start)//2,stop)
# mergeing two lists(sorting the l and r parts)
L[start:stop] = mergesort_2ndstep(l,r)
return L[start:stop]
# START
List_of_nums = []
file_to_open = "input1.txt"
try:
read_file = open(file_to_open,"r")
write_file = open("output.txt","w")
if read_file != None:
# appending every num from file to list_of_nums
for line in read_file:
line = int(line)
List_of_nums.append(line)
# applying mergesort
mergesort_1ststep(List_of_nums,0, len(List_of_nums))
# writing to an output file
# excluding the last element
k = List_of_nums.pop()
for num in List_of_nums:
write_file.write(f"{num}\n")
# writing last element without next line
write_file.write(f"{k}")
# closing files
read_file.close()
write_file.close()
except:
print("file not found")
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