80 lines
3.1 KiB
Rust
80 lines
3.1 KiB
Rust
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/**
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* [2697] Lexicographically Smallest Palindrome
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*
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* You are given a string <code node="[object Object]">s consisting of lowercase English letters, and you are allowed to perform operations on it. In one operation, you can replace a character in <code node="[object Object]">s with another lowercase English letter.
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* Your task is to make <code node="[object Object]">s a palindrome with the minimum number of operations possible. If there are multiple palindromes that can be <meta charset="utf-8" />made using the minimum number of operations, <meta charset="utf-8" />make the lexicographically smallest one.
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* A string a is lexicographically smaller than a string b (of the same length) if in the first position where a and b differ, string a has a letter that appears earlier in the alphabet than the corresponding letter in b.
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* Return the resulting palindrome string.
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*
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* <strong class="example">Example 1:
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*
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* Input: s = "egcfe"
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* Output: "efcfe"
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* Explanation: The minimum number of operations to make "egcfe" a palindrome is 1, and the lexicographically smallest palindrome string we can get by modifying one character is "efcfe", by changing 'g'.
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*
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* <strong class="example">Example 2:
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*
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* Input: s = "abcd"
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* Output: "abba"
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* Explanation: The minimum number of operations to make "abcd" a palindrome is 2, and the lexicographically smallest palindrome string we can get by modifying two characters is "abba".
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*
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* <strong class="example">Example 3:
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*
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* Input: s = "seven"
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* Output: "neven"
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* Explanation: The minimum number of operations to make "seven" a palindrome is 1, and the lexicographically smallest palindrome string we can get by modifying one character is "neven".
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*
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*
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* Constraints:
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*
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* 1 <= s.length <= 1000
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* s consists of only lowercase English letters.
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*
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*/
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pub struct Solution {}
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// problem: https://leetcode.cn/problems/lexicographically-smallest-palindrome/
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// discuss: https://leetcode.cn/problems/lexicographically-smallest-palindrome/discuss/?currentPage=1&orderBy=most_votes&query=
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// submission codes start here
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use std::cmp::min;
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impl Solution {
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pub fn make_smallest_palindrome(s: String) -> String {
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let mut result : Vec<u8> = s.bytes().collect();
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let mut left = 0;
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let mut right = result.len() - 1;
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while left < right {
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if result[left] != result[right] {
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let value = min(result[left], result[right]);
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result[left] = value;
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result[right] = value;
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}
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left = left + 1;
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right = right - 1;
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}
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String::from_utf8(result).unwrap()
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}
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}
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// submission codes end
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_2697() {
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assert_eq!(String::from("efcfe"),
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Solution::make_smallest_palindrome(String::from("egcfe")));
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assert_eq!(String::from("abba"),
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Solution::make_smallest_palindrome(String::from("abcd")));
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assert_eq!(String::from("neven"),
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Solution::make_smallest_palindrome(String::from("seven")));
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}
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}
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