declare class TreeNode {
    val: number;
    char: string;
    left: TreeNode | null;
    right: TreeNode | null;
    /**
     * @param val 字符出现次数
     * @param char 待编码字符
     */
    constructor(val: number, char: string, left?: TreeNode | null, right?: TreeNode | null);
}
export default TreeNode;