Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

reverse words #22

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open
Changes from 1 commit
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 39 additions & 14 deletions lib/reverse_words.rb
Original file line number Diff line number Diff line change
@@ -1,25 +1,50 @@
# A method to reverse each word in a sentence, in place.
require 'pry'
def string_reverse(my_string)
return if my_string == nil || my_string.length < 1
i = 0 #first ele
j = my_string.length - 1 #last ele
while i < j # until position of first ele meets last, so there is the center element in between
temp = my_string[i] #stores frist ele in temp
my_string[i] = my_string[j] #sets first ele to the last ele's position
my_string[j] = temp #sets last element to first ele's position
i += 1 #increment
j -= 1
end
return my_string
i = 0 #first ele
j = my_string.length - 1 #last ele
while i < j # until position of first ele meets last, so there is the center element in between
temp = my_string[i] #stores frist ele in temp
my_string[i] = my_string[j] #sets first ele to the last ele's position
my_string[j] = temp #sets last element to first ele's position
i += 1 #increment
j -= 1
end
return my_string
end

# " evol "

def reverse_words(my_words)
# puts my_words
unless my_words == nil || my_words.empty?
my_words.
string_reverse(my)
last = 0
first = 0
until last == my_words.length - 1
while my_words[first] == " " && first != my_words.length - 1
first += 1
end
last = first
while my_words[last] != " " && last != my_words.length - 1
last += 1
end
if first == last || last == my_words.length - 1
my_words[first..last] = string_reverse(my_words[first..last])

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I didn't see any comments on time and space complexity. As we saw in the first few slides of https://drive.google.com/file/d/0B__DV26QHsH4bWJmS1A0QXBad1U/view?usp=sharing because of using the substring method e.g. my_words[first..last], your space complexity will be O(n).

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Can you think of a solution by updating your string_reverse method to take two additional parameters first and last along with the complete my_words and then only reversing the characters in my_words from index first to index last?

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Once you've given it some thought, take a look at the solution at https://github.com/Ada-C10/reverse_words/blob/solution/lib/reverse_words.rb

else
my_words[first..last - 1] = string_reverse(my_words[first..last - 1])
end
first = last
end
end
# puts "finished #{my_words}"
end


#1, check if first character is " "
#check if the index to the right of it (the next highest index) is a space
#if true, that section is one word
# (the beginning and end of each word needs an index)
#once i find a since word section call string_reverse helper method on it
#else, continue incrementation +1

# "En gineer"
# "reenig nE"
Expand Down