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70 lines
1.5 KiB
Markdown
70 lines
1.5 KiB
Markdown
# [58. Length of Last Word](https://leetcode.com/problems/length-of-last-word/)
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## 题目
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Given a string `s` consisting of some words separated by some number of spaces, return *the length of the **last** word in the string.*
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A **word** is a maximal substring consisting of non-space characters only.
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**Example 1:**
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```
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Input: s = "Hello World"
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Output: 5
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Explanation: The last word is "World" with length 5.
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```
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**Example 2:**
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```
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Input: s = " fly me to the moon "
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Output: 4
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Explanation: The last word is "moon" with length 4.
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```
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**Example 3:**
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```
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Input: s = "luffy is still joyboy"
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Output: 6
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Explanation: The last word is "joyboy" with length 6.
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```
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**Constraints:**
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- `1 <= s.length <= 104`
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- `s` consists of only English letters and spaces `' '`.
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- There will be at least one word in `s`.
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## 题目大意
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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。
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## 解题思路
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- 先从后过滤掉空格找到单词尾部，再从尾部向前遍历，找到单词头部，最后两者相减，即为单词的长度。
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## 代码
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```go
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package leetcode
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func lengthOfLastWord(s string) int {
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last := len(s) - 1
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for last >= 0 && s[last] == ' ' {
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last--
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}
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if last < 0 {
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return 0
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}
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first := last
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for first >= 0 && s[first] != ' ' {
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first--
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}
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return last - first
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}
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``` |