Reverse a string

Solution

Two-Pointer Approach

const reverseString = (str) => {
    let charArray = str.split()
    let left = 0 
    let right = str.length - 1

    while(left <= right){
      const leftLetter = str[left]
      const rightLetter = str[right]
      charArray[right] = leftLetter
      charArray[left] = rightLetter
      left += 1
      right -= 1
    }
    
    return charArray.join('')
  }

Explanation

The function reverseString takes a string as an argument and returns the reversed string. We first convert the string into an array of characters using the split() method. We then use a two-pointer approach to swap the characters at the left and right ends of the array. We continue swapping characters until the left pointer is greater than the right pointer. Finally, we join the array back into a string and return it.

Time Complexity

The time complexity is O(n) because we are iterating through the string once.

Built-in Methods

const reverseString = (str) => {
    return str.split('').reverse().join('');
}

Explanation

The split() method is used to split a string into an array of substrings, and returns the new array. The reverse() method is used to reverse the elements in an array. The join() method is used to join all elements of an array into a string.

Time Complexity

The time complexity is O(n) because we are iterating through the string once.