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@FelixCJF
FelixCJF committed Mar 1, 2017
1 parent f59cd60 commit 836dc34
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228 changes: 228 additions & 0 deletions group02/1554421063/src/com/github/FelixCJF/coding2017/coderising/array/ArrayUtil.java
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package com.github.FelixCJF.coding2017.coderising.array;

import java.util.ArrayList;

public class ArrayUtil {

/**
* 给定一个整形数组a , 对该数组的值进行置换
例如： a = [7, 9 , 30, 3] , 置换后为 [3, 30, 9,7]
如果 a = [7, 9, 30, 3, 4] , 置换后为 [4,3, 30 , 9,7]
* @param origin
* @return
*/
public void reverseArray(int[] origin){
int array[] = new int[origin.length];
for (int i = 0; i<origin.length; i++) {
array[i] = origin[origin.length - 1 - i];
}
System.arraycopy(array, 0, origin, 0, origin.length);
}

/**
* 现在有如下的一个数组： int oldArr[]={1,3,4,5,0,0,6,6,0,5,4,7,6,7,0,5}
* 要求将以上数组中值为0的项去掉，将不为0的值存入一个新的数组，生成的新数组为：
* {1,3,4,5,6,6,5,4,7,6,7,5}
* @param oldArray
* @return
*/

public int[] removeZero(int[] oldArray){
int zero = 0;
//统计原来数组0的个数
for (int i = 0; i < oldArray.length; i++) {
if (oldArray[i] == 0) {
zero ++;
}
}
int[] newArr = new int[oldArray.length - zero];
int count = 0;
for (int i = 0; i<oldArray.length; i ++) {
if (oldArray[i] != 0) {
newArr[count] = oldArray[i];
count ++;
}
}
return newArr;
}

/**
* 给定两个已经排序好的整形数组， a1和a2 , 创建一个新的数组a3, 使得a3 包含a1和a2 的所有元素， 并且仍然是有序的
* 例如 a1 = [3, 5, 7,8] a2 = [4, 5, 6,7] 则 a3 为[3,4,5,6,7,8] , 注意： 已经消除了重复
* @param array1
* @param array2
* @return
*/

public int[] merge(int[] array1, int[] array2){
//创建新数组
int length1 = array1.length;
int length2 = array2.length;
int length = length1 + length2;
int[] newArr = new int[length];
//插入
for (int i = 0; i < length1; i++) {
newArr[i] = array1[i];
}
for (int i = 0; i < length2; i++) {
newArr[length1 - 1 + i] = array2[i];
}
//排序
for (int i = 0; i < length-1; i ++){
if (newArr[i] > newArr[i+1]) {
int temp = newArr[i];
newArr[i] = newArr[i+1];
newArr[i + 1] = temp;
}
}
return newArr;
}
/**
* 把一个已经存满数据的数组 oldArray的容量进行扩展， 扩展后的新数据大小为oldArray.length + size
* 注意，老数组的元素在新数组中需要保持
* 例如 oldArray = [2,3,6] , size = 3,则返回的新数组为
* [2,3,6,0,0,0]
* @param oldArray
* @param size
* @return
*/
public int[] grow(int [] oldArray, int size){
int newArr[] = new int[oldArray.length + size];
System.arraycopy(oldArray, 0, newArr, 0, oldArray.length);
return newArr;
}

/**
* 斐波那契数列为：1，1，2，3，5，8，13，21...... ，给定一个最大值， 返回小于该值的数列
* 例如， max = 15 , 则返回的数组应该为 [1，1，2，3，5，8，13]
* max = 1, 则返回空数组 []
* @param max
* @return
*/
public int[] fibonacci(int max){
int[] newArr;
int f1 = 0;
int f2 = 1;
int f = 0;
if (max < 2) {
return newArr = new int[0];
}
ArrayList list = new ArrayList();
for (int i = 2; f < max; i++) {
list.add(f2);
f = f1 + f2;
f1 = f2;
f2 = f;
}
newArr = new int[list.size()];
for (int i = 0; i < newArr.length; i++) {
newArr[i] = (int) list.get(i);
}
return newArr;
}

/**
* 返回小于给定最大值max的所有素数数组
* 例如max = 23, 返回的数组为[2,3,5,7,11,13,17,19]
* @param max
* @return
*/
public int[] getPrimes(int max){

ArrayList list = new ArrayList();

for (int i = 1; i < max; i++) {
if (isPrime(i)) {
list.add(i);
}
}
int[] newArr = new int[list.size()];
for (int i = 0; i < newArr.length; i++) {
newArr[i] = (int) list.get(i);
}
return newArr;
}
//判断是否为素数
private boolean isPrime(int a) {

boolean flag = true;

if (a < 2) {// 素数不小于2
return false;
} else {

for (int i = 2; i <= Math.sqrt(a); i++) {

if (a % i == 0) {// 若能被整除，则说明不是素数，返回false

flag = false;
break;// 跳出循环
}
}
}
return flag;
}

/**
* 所谓“完数”， 是指这个数恰好等于它的因子之和，例如6=1+2+3
* 给定一个最大值max， 返回一个数组， 数组中是小于max 的所有完数
* @param max
* @return
*/
public int[] getPerfectNumbers(int max){
int[] newArr;
if (max == 0) {
return newArr = new int[0];
}
ArrayList list = new ArrayList();
for (int i = 1; i < max; i++) {
if (isWanshu(i)) {
list.add(i);
}
}
newArr = new int[list.size()];
for (int i = 0; i < newArr.length; i++) {
newArr[i] = (int) list.get(i);
}
return newArr;
}
//判断一个数是不是完数
private boolean isWanshu(int n)
{
boolean flag=false;
int i,sum=0;
for(i=1;i<=n/2;i++)
{
if(n%i==0)
{
sum+=i;
}
}
if(sum==n)
{
flag=true;
}
return flag;
}
/**
* 用seperator 把数组 array给连接起来
* 例如array= [3,8,9], seperator = "-"
* 则返回值为"3-8-9"
* @param array
* @param s
* @return
*/
public String join(int[] array, String seperator){
String string = "";
for (int i = 0; i < array.length; i++) {
if (i == array.length - 1) {
string += array[i];
} else {
string += array[i] + seperator;
}
}
return string;
}


}
148 changes: 148 additions & 0 deletions ...02/1554421063/src/com/github/FelixCJF/coding2017/coderising/array/test/ArrayUtilTest.java
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package com.github.FelixCJF.coding2017.coderising.array.test;

import static org.junit.Assert.*;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

import com.github.FelixCJF.coding2017.coderising.array.ArrayUtil;


public class ArrayUtilTest
{
private ArrayUtil myArray;
@Before
public void setUp() throws Exception
{
myArray = new ArrayUtil();
}

@Test
public void testReverseArray()
{
int[] a = {1, 2, 1, 3, 5, 6};
int[] b = {6, 5, 3, 1, 2, 1};
int[] c = new int[0];

myArray.reverseArray(a);
assertArrayEquals(a, b);

//对空数组进行反转
myArray.reverseArray(c);
assertArrayEquals(c, new int[0]);
}

@Test
public void testRemoveZero()
{
int[] oldArr= {1, 3, 4, 5, 0, 0, 6, 6, 0, 5, 4, 7, 6, 7, 1, 2, 0, 5};
int b[] = {1, 3, 4, 5, 6, 6, 5, 4, 7, 6, 7, 1, 2, 5};
int[] c = myArray.removeZero(oldArr);
assertArrayEquals(b, c);

int[] d = new int[0];
assertArrayEquals(d, new int[0]);
}

@Test
public void testMerge()
{
int a1[] = {1, 2, 3, 4, 5};
int b1[] = {3, 4, 5, 6, 7, 8};
int c1[] = {1, 2, 3, 4, 5, 6, 7, 8};
int[] newArray1 = myArray.merge(a1, b1);
assertArrayEquals(c1, newArray1);

int a2[] = new int[0];
int b2[] = {0, 2, 3, 6, 7, 8};
int c2[] = {0, 2, 3, 6, 7, 8};
int[] newArray2 = myArray.merge(a2, b2);
assertArrayEquals(c2, newArray2);

int a3[] = {0, 2, 3, 6, 7, 8};
int b3[] = new int[0];
int c3[] = {0, 2, 3, 6, 7, 8};
int[] newArray3 = myArray.merge(a3, b3);
assertArrayEquals(c3, newArray3);

int[] a4 = new int[0];
int[] b4 = new int[0];
int[] newArray4 = myArray.merge(a4, b4);
assertArrayEquals(new int[0], newArray4);
}

@Rule
public ExpectedException expectedEx = ExpectedException.none();
@Test
public void testGrow()
{
int[] a = {3, 5, 7, 8, 9};
int[] b = {3, 5, 7, 8, 9, 0, 0, 0};
int[] newArray = myArray.grow(a, 3);
assertArrayEquals(b, newArray);

// size < 0 抛出异常
expectedEx.expect(Exception.class);
int[] newArray1 = myArray.grow(a, -3);
assertArrayEquals(b, newArray1);

}

@Test
public void testFibonacci()
{
//max == 1时返回空数组
int[] array1 = myArray.fibonacci(1);
int[] b = new int[0];
assertArrayEquals(array1, b);


int[] array2= myArray.fibonacci(35);
int[] c = {1, 1, 2, 3, 5, 8, 13, 21, 34 };
assertArrayEquals(c, array2);
}

@Test
public void testGetPrimes()
{
int[] a = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31 };
int[] array1 = myArray.getPrimes(35);
assertArrayEquals(a, array1);

//max <= 2的时候没有素数，数组为空数组 new int[0]
int[] array2 = myArray.getPrimes(1);
int[] b = new int[0];
assertArrayEquals(array2, b);
}

@Test
public void testGetPerfectNumbers()
{
int[] array = myArray.getPerfectNumbers(10000);
int[] a = {6, 28, 496, 8128 };
assertArrayEquals(a, array);
}

@Test
public void testJoin()
{
int[] Array0 = {3, 5, 7, 8, 9};
String s0 = myArray.join(Array0, "-");
String s1 = "3-5-7-8-9";
assertEquals(s1, s0);

int[] Array1 = {3};
String s2 = myArray.join(Array1, "-");
String s3 = "3";
assertEquals(s2, s3);

//传递空数组时，返回空数组
int[] Array2 = new int[0];
String s4 = myArray.join(Array2, "-");
String s5 = "";
assertEquals(s4, s5);
}

}
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