Problem
Write a function that takes a string as input and returns the string reversed.
ExampleGiven s = "hello", return "olleh".
Solution1. Two-Pointer --3ms
public class Solution { public String reverseString(String s) { char[] str = s.toCharArray(); int left = 0, right = str.length-1; while (left < right) { char temp = str[left]; str[left] = str[right]; str[right] = temp; left++; right--; } return new String(str); } }
2. StringBuilder --5ms
public class Solution { public String reverseString(String s) { return new StringBuilder(s).reverse().toString(); } }
3. Recursion --22ms
public class Solution { public String reverseString(String s) { int len = s.length(); if (len <= 1) return s; String leftStr = s.substring(0, len / 2); String rightStr = s.substring(len / 2, len); return reverseString(rightStr) + reverseString(leftStr); } }
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