Reverse words in a given string

Problem Statement - link #

Given a String S, reverse the string without reversing its individual words. Words are separated by dots.

Your Task: You dont need to read input or print anything. Complete the function reverseWords() which takes string S as input parameter and returns a string containing the words in reversed order. Each word in the returning string should also be separated by ‘.’

Expected Time Complexity: O(|S|)
Expected Auxiliary Space: O(|S|)

Examples #

Example 1:

Input:
S = i.like.this.program.very.much
Output: much.very.program.this.like.i
Explanation: After reversing the whole
string(not individual words), the input
string becomes
much.very.program.this.like.i

Example 2:

Input:
S = pqr.mno
Output: mno.pqr
Explanation: After reversing the whole
string , the input string becomes
mno.pqr

Constraints #

• 1 <=|S|≤ 2000

Solutions #

class Solution{
    public:
    //Function to reverse words in a given string.
    string reverseWords(string S) 
    { 
        // code here 
        int i = 0, j = 0;
        while( i < S.size()){
            while( j < S.size() && S[j]!='.') j++;
            reverse(S.begin()+i, S.begin()+j);
            i = j + 1;
            j = i;
        }
        reverse(S.begin(), S.end());
        return S;
    } 
};