【华为机考E卷】-“计算三叉搜索树的高度”题解思路java

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C0E23 计算三叉搜索树的高度

真题链接：【持续更新】2024华为 OD 机试E卷 机考真题库清单（全真题库）

思路

Java

import java.util.Scanner;

public class C0E23 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();

        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = in.nextInt();
        }

        Node root = new Node(arr[0]);
        for (int i = 1; i < n; i++) {
            root.down(arr[i]);
        }

        System.out.println(root.height());
    }

    /**
     * 三叉树
     */
    public static class Node {
        public int val;

        public Node left;
        public Node middle;
        public Node right;

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

        /**
         * 插入规则
         * @param x
         */
        public void down(int x) {
            if (x < val - 500) {
                if (left == null) {
                    left = new Node(x);
                } else {
                    left.down(x);
                }
            } else if (x > val + 500) {
                if (right == null) {
                    right = new Node(x);
                } else {
                    right.down(x);
                }
            } else {
                if (middle == null) {
                    middle = new Node(x);
                } else {
                    middle.down(x);
                }
            }
        }

        /**
         * 求高度
         * @return
         */
        public int height() {
        	// 子树高度
            int leftHeight = left == null ? 0 : left.height();
            int middleHeight = middle == null ? 0 : middle.height();
            int rightHeight = right == null ? 0 : right.height();
            // 当前节点高度 = 1 + 子树的最大高度
            return 1 + Math.max(leftHeight, Math.max(middleHeight, rightHeight));
        }
    }
}

总结

1、封装对象，利用对象的父子关系去递归。

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算法要多练多练多练！！