#Author: Maple0

#Github:https://github.com/Maple0

#11th Aug 2016

#Giving a string, move the first n numbers of characters(0 to n) to the end of the string.

#For example, a given string "abcdefg", move the first 2 characters "ab" to the end of the string

#so that the output is "cdefgab"

def reverse_string_left(string,n):

length=len(string)

if n <=0 or length ==0 or n>length:

return string

left_move_string(string,0,n-1)

left_move_string(string,n,length-1)

left_move_string(string,0,length-1)

return string

#Giving a string, move the last n numbers of the characters(0 to n) to the start of the string.

#For example, a given string "abcdefg", move the last 2 characters "fg" to the end of the string

#so that the output is "fgabcde"

def reverse_string_right(string,n):

length=len(string)

if n <=0 or length ==0 or n>length:

return string

left_move_string(string,0,length-1-n)

left_move_string(string,length-n,length-1)

left_move_string(string,0,length-1)

return string

def left_move_string(string,start,end):

while start < end:

tmp=string[start]

string[start]=string[end]

string[end]=tmp

start=start+1

end=end-1

return string

string=["a","b","c","d","e","f","g"]

print(reverse_string_left(string,2))

string=["a","b","c","d","e","f","g"]

print(reverse_string_right(string,2))