I have solved this problem, but still feel I could improve in some areas.
I know this problem can be solved using slicing and reversed build- in functions.But I am doing this as a practice for interview coding questions.So wanted this way
How did I approach in solving the problem:
- Covert the input string to a list . I did this since in python strings are immutable.
- Reverse the entire list of characters
- Reverse the individual words.
- #Problem area:Once the list is ready with the words reversed , joining back to a string dealing with spaces seems to be problematic to me.
ex: INPUT:' helpful is overflow stack ' -- > Output 'stack overflow is helpful'
## My Code ##
class Solution:
# @param word, a list of chars
# @param startInd, an int
# @param endInd, an int
# @return a list of reversed characters
def reverseChars(self,word,starIndex,endIndex):
lengthWord = endIndex-starIndex+1
# Reverse the characters of the word by swapping the corresponding chars
# Looping for only lengthWord/2 times should suffice
for i in xrange(0,lengthWord/2):
word[starIndex + i],word[endIndex-i]=word[endIndex-i],word[starIndex +i]
return word
# @param s, a string
# @return a string
def reverseWords(self, s):
#Convert given input string into list of characters.
listChars = list(s)
#First reverse the entire string.
self.reverseChars(listChars,0,len(listChars)-1)
# Iterate through the list of reversed chars and reverse individual word.
# Iterate through the list till we find a space and then call the reverseChars function.
startind = 0
endind = -1
space = ' '
for x in listChars:
if(x == space):
if(listChars[startind]== startind<len(listChars)-1):
startind+=1
endind+=1
else:
self.reverseChars(listChars,startind,endind)
endind = endind+1
startind = endind + 1
else:
endind+=1
self.reverseChars(listChars,startind,endind)
--> return ' '.join(''.join(listChars).split())
Can my last return statement with join statements be improved?
