力扣： 1400. 构造 K 个回文字符串

class Solution {
    public boolean canConstruct(String s, int k) {
        int right = s.length();
        int[] occ = new int[26];
        for (int i = 0; i < right; i++){
            occ[s.charAt(i) - 'a']++;
        }

        int left = 0;
        for (int i = 0; i < 26; i++){
            if (occ[i] % 2 == 1){
                ++left;
            }
        }
        left = Math.max(left, 1);
        return left <= k && k <= right;
    }
}