判定二分查找树

有一半的代码都在处理输入格式：

import java.util.*;
class TreeNode{    //定义树节点
    int val;
    TreeNode left, right;
    TreeNode(int n){val = n;}
}
public class Main {
    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(System.in);
        Map<Integer, TreeNode> m = new HashMap<>();    //用节点值映射树节点
        m.put(-1, null);
        int r = Integer.parseInt(sc.nextLine());    //根节点
        m.put(r, new TreeNode(r));
        while(sc.hasNextLine()){
            String[] v1 = sc.nextLine().split(":");    //处理这奇葩的输入
            String[] v2 = v1[1].split("[|]");
            int lf = Integer.parseInt(v2[0]), rt = Integer.parseInt(v2[1]);
            if(lf != -1) m.put(lf, new TreeNode(lf));
            if(rt != -1) m.put(rt, new TreeNode(rt));
            m.get(Integer.parseInt(v1[0])).left = m.get(lf);
            m.get(Integer.parseInt(v1[0])).right = m.get(rt);
        }
        if(h(m.get(r))) System.out.println(1);
        else System.out.println(0);
    }
    static int f(TreeNode r){    //求一棵树的最大节点值
        if(r == null) return Integer.MIN_VALUE;
        return Math.max(Math.max(f(r.left), f(r.right)), r.val);
    }
    static int g(TreeNode r){    //求一棵树的最小节点值
        if(r == null) return Integer.MAX_VALUE;
        return Math.min(Math.min(g(r.left), g(r.right)), r.val);
    }
    static boolean h(TreeNode r){    //判断BST
        if(r == null) return true;
        return r.val > f(r.left) && r.val < g(r.right) && h(r.left) && h(r.right);
    }
}