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58. 最后一个单词的长度


58. 最后一个单词的长度

🟢   🔖  字符串  🔗 力扣open in new window LeetCodeopen in new window

题目

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.

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.

Constraints:

  • 1 <= s.length <= 10^4
  • s consists of only English letters and spaces ' '.
  • There will be at least one word in s.

题目大意

给你一个字符串  s,由若干单词组成,单词前后用一些空格字符隔开。返回字符串中最后一个单词的长度。单词  是指仅由字母组成、不包含任何空格字符的最大子字符串。

解题思路

  • trim 过滤掉尾部的空格,再用最后一个字符的下标,减去最后一个空格下标,即为单词的长度。

代码

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLastWord = function (s) {
	s = s.trim();
	return s.length - 1 - s.lastIndexOf(' ');
};