Viiisit [LeetCode] - 58. Length of Last Word

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Problem - Length of Last Word

Given a string s consisting of words and spaces, return the length of the last word in the string.

A word is a maximal substring consisting of non-space characters only.

翻譯蒟蒻

要回傳整個字串中的最後一個字母的長度。

• Example 1:

  Input: s = "Hello World"
  Output: 5
  Explanation: The last word is "World" with length 5.

• Example 2:

  Input: s = "   fly me   to   the moon  "
  Output: 4
  Explanation: The last word is "moon" with length 4.

• Example 3:

  Input: s = "luffy is still joyboy"
  Output: 6
  Explanation: The last word is "joyboy" with length 6.

---

Solution - JavaScript

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLastWord = function(s) {
  // 移除前後空白格
  let trimmedString = s.trim();

  let length = 0;
  for (let i = trimmedString.length - 1; i >= 0; i--) {
    if (trimmedString[i] === " ") {
      break;
    }
    length++;
  }

  return length;
};

Solution - Ruby

def length_of_last_word(s)
  # 用 strip 移除空白格
  trimmed_s = s.strip
  length = 0
  (trimmed_s.length - 1).downto(0).each do |i|
    if trimmed_s[i] == " "
      break
    end
    length += 1
  end
  length
end

Solution - PHP

function lengthOfLastWord($s) {
    $trimmedString = trim($s);
    $length = 0;
    for ($i = strlen($trimmedString) - 1; $i >= 0; $i--) {
        if ($trimmedString[$i] === " ") {
            break;
        }
        $length++;
    }
    return $length;
}

$s = "Hello World";
$result = lengthOfLastWord($s);
echo "Length of the last word: " . $result; // Length of the last word: 5

PHP 方法筆記

• trim 用於刪除字串開頭和結尾空白字符函數。這些空白字符包括空格、換行符、制表符等。

  $str = "   Hello, World!   ";
  $trimmedStr = trim($str);
  
  echo "原始字串: '$str'\n";
  echo "刪除空白後的字串: '$trimmedStr'";
  
  // Output: 原始字串: '   Hello, World!   '
  // Output: 刪除空白後的字串: 'Hello, World!'

LeetCode 傳送門 - Length of Last Word