HappyLeetcode1 Reverse Words in a String

Happyleetcode1:reverse Words in a string topic description:

Topic thinking:

1. Create an array that stores one word per array.
2. Output the array in reverse, followed by a space after each word output.

Topic Problem Solving Code python

Class Solution:

# @param s, a string

# @return A string

def reversewords (self, s):

Slist=[]

Slist=s.split ()

For I in range (len (slist)/2):

Slist[i],slist[len (slist) -1-i]=slist[len (slist) -1-i],slist[i]

Return '. Join (Slist)

C++

Class Solution {

Public

void Reversewords (String &s) {

if (S.empty ())

Return

Remove heading and trailing spaces

int i = 0;

while (I<s.size () && s[i] = = ")

i++;

if (i = = S.size ())

{

s = "";

Return

}

Int J = s.size ()-1;

while (j>=0 && s[j] = = ")

j--;

if (j = =-1)

{

s = "";

Return

}

s = s.substr (i,j-i + 1);

size_t pos = 0;

Vector<string> STRs;

size_t begin = 0;

while (Begin < S.size ())

{

pos = s.find_first_of (", begin);

if (pos = = begin)

{

begin++;

Continue

}

else if (pos! =-1)

Strs.push_back (S.substr (Begin,pos-begin));

else//pos = =-1, the end

{

Strs.push_back (S.substr (Begin,s.size ()-1-begin + 1));

Break

}

Begin = pos + 1;

}

String ans;

for (int i = Strs.size ()-1; i > 0; i--)

{

Ans + = strs[i];

Ans + = "";

}

Ans + = strs[0];

s = ans;

}

};

Post-Title Summary

1. ". Join (Slist) is a divine expression of a list-to-string.

Official answers

One simple approach was a two-pass Solution:first pass to split the string by spaces into an array of words and then second P Extract the words in reversed order.

We can do better in One-pass. While iterating the string in reverse order, we keep track of a word ' s begin and end position. When we is at the beginning of a word, we append it.

HappyLeetcode1 Reverse Words in a String