75 lines
1.3 KiB
Markdown
75 lines
1.3 KiB
Markdown
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# 3518. Smallest Palindromic Rearrangement II
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You are given a string `s` and an integer `k`.
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Return the k-th palindromic of `s`. If there are fewer than `k` distinct palindromic permutations, return an empty string.
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Note: Different rearrangements that yield the same palindromic string are considered identical and are counted once.
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## Example 1
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**Input:**
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```text
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s = "abba", k = 2
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````
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**Output:**
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```text
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"baab"
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```
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**Explanation:**
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The two distinct palindromic rearrangements of `"abba"` are `"abba"` and `"baab"`.
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Lexicographically, `"abba"` comes before `"baab"`. Since `k = 2`, the output is `"baab"`.
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## Example 2
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**Input:**
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```text
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s = "aa", k = 2
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```
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**Output:**
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```text
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""
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```
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**Explanation:**
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There is only one palindromic rearrangement: `"aa"`.
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The output is an empty string since `k = 2` exceeds the number of possible rearrangements.
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## Example 3
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**Input:**
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```text
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s = "bacab", k = 1
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```
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**Output:**
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```text
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"abcba"
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```
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**Explanation:**
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The two distinct palindromic rearrangements of `"bacab"` are `"abcba"` and `"bacab"`.
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Lexicographically, `"abcba"` comes before `"bacab"`. Since `k = 1`, the output is `"abcba"`.
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## Constraints
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* `1 <= s.length <= 104`
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* `s` consists of lowercase English letters.
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* `s` is guaranteed to be palindromic.
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* `1 <= k <= 106`
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