1816. Truncate Sentence

# 1816. Truncate Sentence#

## 题目 #

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).

• For example, “Hello World”, “HELLO”, and “hello world hello world” are all sentences.

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.

Example 1:

``````Input: s = "Hello how are you Contestant", k = 4
Output: "Hello how are you"
Explanation:
The words in s are ["Hello", "how" "are", "you", "Contestant"].
The first 4 words are ["Hello", "how", "are", "you"].
Hence, you should return "Hello how are you".
``````

Example 2:

``````Input: s = "What is the solution to this problem", k = 4
Output: "What is the solution"
Explanation:
The words in s are ["What", "is" "the", "solution", "to", "this", "problem"].
The first 4 words are ["What", "is", "the", "solution"].
Hence, you should return "What is the solution".
``````

Example 3:

``````Input: s = "chopper is not a tanuki", k = 5
Output: "chopper is not a tanuki"
``````

Constraints:

• 1 <= s.length <= 500
• k is in the range [1, the number of words in s].
• s consist of only lowercase and uppercase English letters and spaces.
• The words in s are separated by a single space.
• There are no leading or trailing spaces.

## 题目大意 #

• 例如，“Hello World”、“HELLO” 和 “hello world hello world” 都是句子。

## 解题思路 #

• 遍历字符串 s，找到最后一个空格的下标 end
• 如果 end 为 0，直接返回 s,否则返回 s[:end]

## 代码 #

``````package leetcode

func truncateSentence(s string, k int) string {
end := 0
for i := range s {
if k > 0 && s[i] == ' ' {
k--
}
if k == 0 {
end = i
break
}
}
if end == 0 {
return s
}
return s[:end]
}
`````` Jun 22, 2022 Edit this page