LeetCode-in-Java

1400. Construct K Palindrome Strings

Medium

Given a string s and an integer k, return true if you can use all the characters in s to construct k palindrome strings or false otherwise.

Example 1:

Input: s = “annabelle”, k = 2

Output: true

Explanation: You can construct two palindromes using all characters in s. Some possible constructions “anna” + “elble”, “anbna” + “elle”, “anellena” + “b”

Example 2:

Input: s = “leetcode”, k = 3

Output: false

Explanation: It is impossible to construct 3 palindromes using all the characters of s.

Example 3:

Input: s = “true”, k = 4

Output: true

Explanation: The only possible solution is to put each character in a separate string.

Constraints:

• 1 <= s.length <= 105
• s consists of lowercase English letters.
• 1 <= k <= 105

Solution

public class Solution {
    public boolean canConstruct(String s, int k) {
        if (s.length() == k) {
            // if size is same as k we can separate out all letters
            return true;
        }
        if (s.length() < k) {
            // if size is less than it is not possible
            return false;
        }
        // count occurrence of each letter
        int[] count = new int[26];
        for (char curr : s.toCharArray()) {
            count[curr - 'a']++;
        }
        // reduce k whenever count is odd
        for (int i = 0; i < 26; i++) {
            if (count[i] % 2 != 0) {
                k--;
            }
        }
        // we can have max k odd characters
        return k >= 0;
    }
}

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