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520. Detect Capital

題目​

Detect Capital

完整題目

We define the usage of capitals in a word to be right when one of the following cases holds:

  • All letters in this word are capitals, like "USA".
  • All letters in this word are not capitals, like "leetcode".
  • Only the first letter in this word is capital, like "Google".

Given a string word, return true if the usage of capitals in it is right.

Example 1

Input: word = "USA"
Output: true

Example 2

Input: word = "FlaG"
Output: false

Constraints:

  • 1 <= word.length <= 100
  • word consists of lowercase and uppercase English letters.

檢查題目給的文字是否符合全大寫 or 全小寫 or 第一字大小其他泉小寫的規則。

題目難易度​

Easy

解題想法​

把每個規則的正規式都寫出來，再分別去測試是否符合正規式條件，若有一符合則回傳 true。

初試​

Runtime: 52ms, 99.73%

Memory Usage: 42MB, 87.77%

每個

/**
 * @param {string} word
 * @return {boolean}
 */
var detectCapitalUse = function (word) {
  let re = false;
  const allCapitals = new RegExp("^[A-Z]+$");
  const allNCapitals = new RegExp("^[a-z]+$");
  const oneCapitals = new RegExp("^[A-Z]{1}[a-z]+$");

  if (allCapitals.test(word)) re = true;
  if (allNCapitals.test(word)) re = true;
  if (oneCapitals.test(word)) re = true;
  return re;
};