1400. Construct K Palindrome Strings

Problem

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 <= 10^5

• s consists of lowercase English letters.

• 1 <= k <= 10^5

Solution (Java)

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;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).