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 sโโโโโโ and an integer kโโโโโโ. You want to truncate sโโโโโโ such that it contains only the first kโโโโโโ words. Return sโโโโโโ 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 <= 500kis in the range[1, the number of words in s].sconsist of only lowercase and uppercase English letters and spaces.- The words in
sare separated by a single space. - There are no leading or trailing spaces.
Solution:
Time complexity: O(n)
Space complexity: O(n)
C++
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class Solution { public: string truncateSentence(string s, int k) { string ans; stringstream ss(s); for (int i = 0; i < k && ss; ++i) { string word; ss >> word; ans += (ans.empty() ? "" : " ") + word; } return ans; } }; |
Python3
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class Solution: def truncateSentence(self, s: str, k: int) -> str: return " ".join(s.split()[:k]) |