Reverse String

2017-05-03

leetcode

Q. Write a function that takes a string as input and returns the string reversed.

Example:
Given s = “hello”, return “olleh”

Answer 1: Using two pointers

/**
 * @param {string} s
 * @return {string}
 */
export default function reverseString (s) {
  const arr = s.split('')
  const half = arr.length / 2 | 0
  for (let i = 0; i < half; i++) {
    const temp = arr[i]
    arr[i] = arr[arr.length - i - 1]
    arr[s.length - i - 1] = temp
  }
  return arr.join('')
}

Answer 2: Using simple string concatenation

/**
 * @param {string} s
 * @return {string}
 */
export default function reverseString (s) {
  let reversed = ''
  for (let i = s.length - 1; i >= 0; i--) {
    reversed += s.charAt(i)
  }
  return reversed
}