Reverse a string or array

Problem Statement

You have given a string A. Your task is to reverse that string.

Example

input: Developersway

output: yawsrepoleveD

Approaches

Approach 1

1. Create an empty string B.

2. Then iterate over string A from its end to the start for each of its characters.

3. Concatenate each character of string A in string B.

Time Complexity : 0(n)

Space Complexity : O(n)

Approach 2

1. Iterate over string A up to half of its length.

   if the length of the string is n then iterate till n/2

2. swap the ith character of string A with the ith character from last.

   1st character is swapped with the last character, and the second character is swapped with the second last character. and so on till n/2.

Time Complexity : 0(n)

Space Complexity: O(1) // here space complexity is constant (lesser then previous)

Code for Approach 2

#include <iostream>
using namespace std;

string reverseWord(string str){
  int n = str.length(); 
  int start = 0;
  int end = n-1;
  while(start < end){
      char temp = str[start];
      str[start] = str[end];
      str[end] = temp;
      start++;
      end--;
  }
  return str;
}
int main()
{
    string A;
    cin>>A;
    cout<<reverseWord(A)<<endl;
    return 0;
}

input: Developersway

output: yawsrepoleveD

Hope this article will help if you have any problem regarding this article feel free to comment.

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