Leetcode

Reverse String

  • Time:O(n)
  • Space:O(1)

C++

class Solution {
 public:
  void reverseString(vector<char>& s) {
    int l = 0;
    int r = s.size() - 1;

    while (l < r)
      swap(s[l++], s[r--]);
  }
};

JAVA

class Solution {
  public void reverseString(char[] s) {
    int l = 0;
    int r = s.length - 1;

    while (l < r) {
      char temp = s[l];
      s[l++] = s[r];
      s[r--] = temp;
    }
  }
}

Python

class Solution:
  def reverseString(self, s: List[str]) -> None:
    l = 0
    r = len(s) - 1

    while l < r:
      s[l], s[r] = s[r], s[l]
      l += 1
      r -= 1