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76 lines
2.3 KiB
Markdown
76 lines
2.3 KiB
Markdown
# [1816. Truncate Sentence](https://leetcode.com/problems/truncate-sentence/)
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## 题目
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A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each of the words consists of only uppercase and lowercase English letters (no punctuation).
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- For example, "Hello World", "HELLO", and "hello world hello world" are all sentences.
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You are given a sentence s and an integer k. You want to truncate s such that it contains only the first k words. Return s after truncating it.
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**Example 1**:
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Input: s = "Hello how are you Contestant", k = 4
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Output: "Hello how are you"
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Explanation:
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The words in s are ["Hello", "how" "are", "you", "Contestant"].
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The first 4 words are ["Hello", "how", "are", "you"].
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Hence, you should return "Hello how are you".
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**Example 2**:
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Input: s = "What is the solution to this problem", k = 4
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Output: "What is the solution"
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Explanation:
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The words in s are ["What", "is" "the", "solution", "to", "this", "problem"].
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The first 4 words are ["What", "is", "the", "solution"].
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Hence, you should return "What is the solution".
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**Example 3**:
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Input: s = "chopper is not a tanuki", k = 5
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Output: "chopper is not a tanuki"
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**Constraints:**
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- 1 <= s.length <= 500
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- k is in the range [1, the number of words in s].
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- s consist of only lowercase and uppercase English letters and spaces.
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- The words in s are separated by a single space.
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- There are no leading or trailing spaces.
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## 题目大意
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句子 是一个单词列表，列表中的单词之间用单个空格隔开，且不存在前导或尾随空格。每个单词仅由大小写英文字母组成（不含标点符号）。
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- 例如，"Hello World"、"HELLO" 和 "hello world hello world" 都是句子。
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给你一个句子 s 和一个整数 k ，请你将 s 截断使截断后的句子仅含前 k 个单词。返回截断 s 后得到的句子。
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## 解题思路
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- 遍历字符串 s，找到最后一个空格的下标 end
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- 如果 end 为 0，直接返回 s,否则返回 s[:end]
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## 代码
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```go
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package leetcode
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func truncateSentence(s string, k int) string {
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end := 0
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for i := range s {
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if k > 0 && s[i] == ' ' {
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k--
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}
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if k == 0 {
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end = i
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break
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}
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}
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if end == 0 {
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return s
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}
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return s[:end]
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}
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``` |