leetcode

简单递归双指针字符串

方法1 reverse

var reverseString = function (s) {
  return s.reverse();
};

参考资料
mdn Array.prototype.reverse()：链接

方法2 双指针

var reverseString = function (s) {
  let l = 0, r = s.length - 1;
  while (l < r) {
    [s[l], s[r]] = [s[r], s[l]];
    l++; r--;
  }
};

**["h","e","l","l","o"]**

方法3 递归

var reverseString = function (s) {
  const swap = (l, r) => {
    if (l >= r) return;
    [s[l], s[r]] = [s[r], s[l]];
    swap(++l, --r);
  }
  swap(0, s.length - 1);
};

注解
原理和「方法2」相同

⚠️
swap(++l, --r)✅
swap(l++, r--)❌