151. Reverse Words in a String
Given an input string s
, reverse the order of the words.
A word is defined as a sequence of non-space characters. The words in s
will be separated by at least one space.
Return a string of the words in reverse order concatenated by a single space.
Note that s
may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.
Example 1:
Input: s = "the sky is blue" Output: "blue is sky the"
Example 2:
Input: s = " hello world " Output: "world hello" Explanation: Your reversed string should not contain leading or trailing spaces.
Example 3:
Input: s = "a good example" Output: "example good a" Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.
Example 4:
Input: s = " Bob Loves Alice " Output: "Alice Loves Bob"
Example 5:
Input: s = "Alice does not even like bob" Output: "bob like even not does Alice"
Constraints:
1 <= s.length <= 104
s
contains English letters (upper-case and lower-case), digits, and spaces' '
.- There is at least one word in
s
.
Follow up:
- Could you solve it in-place with
O(1)
extra space?
Rust Solution
struct Solution;
impl Solution {
fn reverse_words(s: String) -> String {
s.split_whitespace().rev().collect::<Vec<&str>>().join(" ")
}
}
#[test]
fn test() {
let s: String = "the sky is blue".to_string();
let res: String = "blue is sky the".to_string();
assert_eq!(Solution::reverse_words(s), res);
}
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