/**
 * @param {string} s
 * @return {number}
 */
var longestPalindrome = function (s) {
  let longest = 0;
  let keys = {};

  for (const char of s) {
    keys[char] = (keys[char] || 0) + 1;
    if (keys[char] % 2 === 0) {
      longest += 2;
    }
  }
  return s.length > longest ? longest + 1 : longest;
};

/**
 * @param {number} n
 * @return {string[]}
 */
var fizzBuzz = function (n) {
  const result = [];

  for (let i = 1; i <= n; i++) {
    if (i % 15 === 0) {
      result.push('FizzBuzz');
    } else if (i % 5 === 0) {
      result.push('Buzz');
    } else if (i % 3 === 0) {
      result.push('Fizz');
    } else {
      result.push(i.toString());
    }
  }

  return result;
};

/**
 * @param {string} s
 * @return {number}
 */
var countSegments = function (s) {
  if (s.length === 0) {
    return 0;
  }

  let result = s[0] !== ' ' ? 1 : 0;

  for (let i = 0; i < s.length; i++) {
    if (s[i - 1] === ' ' && s[i] !== ' ') {
      result++;
    }
  }

  return result;
};

/**
 * @param {string} s
 * @return {boolean}
 */
var repeatedSubstringPattern = function (s) {
  // s를 두 번 반복한 후, 첫 글자, 맨 마지막 글자를 제거한 후 그 안에 s가 들어있는지 판별
  return s.repeat(2).slice(1, -1).includes(s);
};

/**
 * @param {string[]} words
 * @return {string[]}
 */
var findWords = function (words) {
  const firstRow = 'qwertyuiop';
  const secondRow = 'asdfghjkl';
  const thirdRow = 'zxcvbnm';

  const result = [];

  for (const word of words) {
    const lowerCaseWord = word.toLocaleLowerCase();
    const a = lowerCaseWord.split('').every((word) => firstRow.includes(word));
    const b = lowerCaseWord.split('').every((word) => secondRow.includes(word));
    const c = lowerCaseWord.split('').every((word) => thirdRow.includes(word));

    if (a || b || c) {
      result.push(word);
    }
  }

  return result;
};

/**
 * @param {string} word
 * @return {boolean}
 */
var detectCapitalUse = function (word) {
  if (word.length === 1) {
    return true;
  }

  const isAllLowerCase = (word) => {
    return word.charCodeAt(0) >= 97 && word.charCodeAt(0) <= 122;
  };
  const isAllUpperCase = (word) => {
    return word.charCodeAt(0) >= 65 && word.charCodeAt(0) <= 90;
  };

  if (isAllLowerCase(word[0])) {
    for (let i = 0; i < word.length; i++) {
      if (!isAllLowerCase(word[i])) {
        return false;
      }
    }
  } else {
    if (isAllLowerCase(word[1])) {
      for (let i = 1; i < word.length; i++) {
        if (!isAllLowerCase(word[i])) {
          return false;
        }
      }
    } else {
      for (let i = 0; i < word.length; i++) {
        if (!isAllUpperCase(word[i])) {
          return false;
        }
      }
    }
  }
  return true;
};

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {boolean}
 */
var isSameTree = function (p, q) {
  if (p === null && q === null) {
    return true;
  }

  if ((p !== null && q === null) || (p === null && q !== null)) {
    return false;
  }

  if (p.val !== q.val) {
    return false;
  }

  return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
};

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {boolean}
 */
var isSymmetric = function (root) {
  return root === null || isMirrorValue(root.left, root.right);
};

const isMirrorValue = (left, right) => {
  if (left === null && right === null) {
    return true;
  }
  if (left === null || right === null) {
    return false;
  }

  if (left.val === right.val) {
    return (
      isMirrorValue(left.right, right.left) &&
      isMirrorValue(left.left, right.right)
    );
  } else {
    return false;
  }
};

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var maxDepth = function (root) {
  if (root === null) {
    return 0;
  }

  return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));
};

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {number[]} nums
 * @return {TreeNode}
 */
var sortedArrayToBST = function (nums) {
  if (nums.length === 0) {
    return null;
  }
  return createBST(nums, 0, nums.length - 1);
};

const createBST = (nums, low, high) => {
  if (low > high) {
    return null;
  }

  let mid = Math.floor((high + low) / 2);

  let node = new TreeNode(nums[mid]);
  node.left = createBST(nums, low, mid - 1);
  node.right = createBST(nums, mid + 1, high);
  return node;
};