北京创新维信公司笔试题 + 本人答案

题目：
排序，在命令行接受用户输入的N个数字， 以-1作为结束标志，并且-1不计算在内，对这些输入的数字进行排序输出，并计算平均数。
要求 1. 自己写排序算法(冒泡,选择等等任选)，不用汉字，拼音做类名，注释等等。
2. 也可以不从命令行输入, 而是直接对数组排序.


创建树，树上每一个节点都是Class Node的实例，Node有name, value属性，其中name和value是初始时已经设好的, 要求用数据结构中的树(不是二叉树)来实现，要求能够保持构造树时添加结点的顺序。构造树的时候可以在代码中写死各个节点值，不用动态输入进行构造树，不用汉字，拼音做类名，注释等等(用递归实现)
要求
1. 写一个方法Node searchNode(String searchName),实现节点查找. 要求在树中查找name值等于searchName的节点，如果找不到，返回NULL, 找到了就返回此节点.
2. 调用searchNode方法查找节点,没有找到节点输出"Not found", 如果找到了就输出此节点name,value值。
构造如下的树，查找节点 Sub 22, Sub 3, Sub 10(找不到)
依次调用
searchNode("Sub 22");
输出 Sub 22, 0
searchNode("Sub 3");
输出 Sub 3, 50
searchNode("Sub 10");
输出 Not found

Root(value:0)--
|--Sub 1 (value:20)
|--Sub 2(value:10)
| |--
| |--Sub 21(value:5)
| |--Sub 22 (value:0)
|--Sub 3 (value:50)
|--
|--Sub 31(value:100)
|--Sub 32(value:200)



我做的程序：


public class ArraySort {

public static void main(String[] args) {
if(args.length == 0){ //estimate the input running arguments
System.out.println("The parameter must be numbers and had better ends with -1 , such as ' java ArraySort 1 34 -1 '");
return;
}
int[] array = generateArray(args);
getAverage(array);
selectionSort(array);
print(array);
}

private static double getAverage(int[] array) {
//get average
double average = 0;
int sum = 0;
for(int i=0; i<array.length; i++){
sum += array[i];
}
average = ((double)sum) / array.length;
System.out.println("The average of the array is " + average);
return average;
}

private static void print(int[] array) {
//print the array
System.out.print("The memebers of the array are : ");
for(int i=0; i><array.length; i++){
System.out.print(array[i] + " ");
}

}

private static int[] generateArray(String[] args) {
// parse String[] to int[]
int temp = 0; //temporarily deposit the parse int
int arraysize = args.length; //deposite the length of the array ,init value = args.length

for(int i=0; i><args.length; i++){ //get the size before "-1"
try{
temp = Integer.parseInt(args[i]);
if(temp == -1){
arraysize = i;
break;
}
}catch(NumberFormatException e){
System.out.println("The parameter must be numbers and had better ends with -1 , such as ' java ArraySort 1 34 -1 '");
System.exit(-1);
}
}

int[] array = new int[arraysize]; //generate the array ,size use the parameter : arraysize
for(int i=0; i><arraysize; i++){
array[i] = Integer.parseInt(args[i]);
}
return array;

}

public static void selectionSort(int[] array){
//selection sort
int flag, temp; //the flag is used to deposit the current smaller number's position
for(int i=0; i><array.length; i++){
flag = i;
for(int j=i+1; j><array.length; j++){
if(array[j] >< array[flag]){
flag = j; //update the smaller number's position
}
}
if(flag != i){ //swap
temp = array[i];
array[i] = array[flag];
array[flag] = temp;
}
}
}
}






import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class Node {
private String name;
private int value;
public List<Node> list; // use jdk5.0's generic

public Node(String name, int value){ //constructor
this.name = name;
this.value = value;
}

public Node searchNode(String searchName) { //the method of searchnode use recursion
if (this.getName().equals(searchName))
return this;

Node node = null;
Iterator<Node> iterator = list.iterator();
while (iterator.hasNext()) {
node = iterator.next();
if (searchName.equals(node.getName()))
return node;
else if (node.list != null)
node.searchNode(searchName); //recursion
}
System.out.println("Not found");
return null;
}

public void addSubNode(String name, int value) { //add sub node
if (list == null){
list = new ArrayList<Node>();
}
Node node = new Node(name, value); //use the constuctor
list.add(node);
}

public String toString() { //override the toString method
return name + ", " + value;
}

public String getName() { //generate getters and setters
return name;
}

public void setName(String name) { //generate getters and setters
this.name = name;
}

public int getValue() { //generate getters and setters
return value;
}

public void setValue(int value) { //generate getters and setters
this.value = value;
}

public static void print(Node n){ //print method , use the overrided toString method
if(n != null){
System.out.println(n);
}
}

public static void main(String[]args){
Node n = new Node("Root", 0); //generate Root node
n.addSubNode("Sub 1", 20); //insert node
n.addSubNode("Sub 2", 10);
n.addSubNode("Sub 21", 5);
n.addSubNode("Sub 22", 0);
n.addSubNode("Sub 3", 50);
n.addSubNode("Sub 31", 100);
n.addSubNode("Sub 32", 200);

print(n.searchNode("Sub 22")); //print the result of search
print(n.searchNode("Sub 3"));
print(n.searchNode("Sub 10"));

}

}

平均得分

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