牛客网：NC60 判断一棵二叉树是否为搜索二叉树和完全二叉树

import java.util.ArrayList;
import java.util.Arrays;

/**
 * @author xienl
 * @description 判断一棵二叉树是否为搜索二叉树和完全二叉树
 * @date 2022/7/6
 */

public class Solution {
    public static void main(String[] args) {
        Solution solution = new Solution();
        TreeNode treeNode = new TreeNode(3, new TreeNode(2, new TreeNode(1),new TreeNode(4)), new TreeNode(5));
        //TreeNode treeNode = new TreeNode(3, new TreeNode(1), new TreeNode(7, new TreeNode(6), new TreeNode(8)));
        System.out.println(Arrays.toString(solution.judgeIt(treeNode)));
    }

    public boolean[] judgeIt (TreeNode root) {
        // write code here
        boolean[] res = new boolean[2];
        res[0] = isSerachTreeBST(root, Integer.MIN_VALUE, Integer.MAX_VALUE);
        res[1] = isAllTreeBST(root);
        return res;
    }

    private boolean isSerachTreeBST(TreeNode root, int left, int right){
        if (root == null){
            return true;
        }
        if ( root.val < left || root.val > right){
            return false;
        }
        return isSerachTreeBST(root.left , left, root.val) && isSerachTreeBST(root.right, root.val, right);
    }

    private boolean isAllTreeBST(TreeNode root){
        if (root == null){
            return true;
        }
        int left = calculation(root.left, 0);
        int right = calculation(root.right, 0);
        if (left != right){
            return false;
        }
        return isAllTreeBST(root.left) && isAllTreeBST(root.right);
    }

    private int calculation(TreeNode root, int n){
        if (root == null){
            return n;
        }
        int leftValue = calculation(root.left, n + 1);
        int rightValue = calculation(root.right, n + 1);
        return Math.max(leftValue, rightValue);
    }
}

class TreeNode {
    int val = 0;
    TreeNode left = null;

    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;
    }

    public TreeNode(int val, TreeNode left, TreeNode right) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}