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Merged
eloiseh merged 1 commit into from
Mar 5, 2017
Merged

Homework 02262017: arrayUtil & litestruts #35

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218 changes: 218 additions & 0 deletions group02/527705641/src/com/github/fei9009/coderising0226/array/ArrayUtil.java
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package com.github.fei9009.coderising0226.array;

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

import com.sun.org.apache.bcel.internal.generic.ISTORE;

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 i = 0, j = origin.length-1;
while(i < j){
int tmp = origin[i];
origin[i] = origin[j];
origin[j] = tmp;
i++;
j--;
}
}

/**
* 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){
if (oldArray == null || oldArray.length == 0){
return oldArray;
}
int count = 0;
for (int i = 0; i < oldArray.length; i++) {
if (oldArray[i] != 0) {
count++;
}
}
int[] newArray = new int[count];
int j = 0;
for (int i = 0; i <= oldArray.length - 1; i++) {
if (oldArray[i] == 0) {
continue;
}
newArray[j++] = oldArray[i];
}
return newArray;
}

/**
* 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){
if (array1 == null && array2 == null) {
return null;
}
if (array1 == null) {
return array2;
}
if (array2 == null) {
return array1;
}
int i=0, j=0, k=0;
int len1 = array1.length;
int len2 = array2.length;
int[] mergeArr = new int[len1+len2];
while(true){
if(i == len1 || j == len2)
break;
if(array1[i]<array2[j]){
mergeArr[k++] = array1[i++];
}else if(array1[i]>array2[j]){
mergeArr[k++] = array2[j++];
}else{
mergeArr[k++] = array1[i++];
j++;
}
}

for(;i<len1;i++){
mergeArr[k++] = array1[i];
}
for(;j<len2;j++){
mergeArr[k++] = array2[j];
}
return Arrays.copyOfRange(mergeArr, 0, k);
}
/**
* 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){
if (oldArray == null) {
return null;
}
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){
if (max == 1) {
return new int[]{};
}
List<Integer> list = new ArrayList<>();
int f1 = 1, f2 = 1, f3;
list.add(f1);
list.add(f2);
while (f1 +f2 < max) {
f3 = f1 + f2;
list.add(f3);
f1 = f2;
f2 = f3;
}
int[] result = new int[list.size()];
int j = 0;
for(Integer i : list) {
result[j++] = i;
}
return result;
}

/**
* 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){
int[] a = new int[max];
int k=0;
for (int z = 1; z<max; z++){
int j = 1;
for (int i = 1; i<z; i++){
if(z%i == 0){
j++;
}
}
if(j == 2){
a[k++] = z;
}
}
return Arrays.copyOfRange(a,0,k);
}

/**
* 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[] a = new int[max];
int k = 0;
for (int i = 1; i <= max; i++) {
int temp = 0;
for (int n = 1; n < i / 2 + 1; n++) {
if (i % n == 0) {
temp += n;
}
}
if (temp == i) {
a[k++] = i;
}
}
return Arrays.copyOfRange(a,0,k);
}

/**
* 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){
if (array.length == 0) {
return "";
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < array.length - 1; i++) {
sb.append(Integer.toString(array[i]));
sb.append(seperator);
}
sb.append(Integer.toString(array[array.length-1]));
String result = sb.toString();
return result;
}


}
153 changes: 153 additions & 0 deletions group02/527705641/src/com/github/fei9009/coderising0226/array/ArrayUtilTest.java
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package com.github.fei9009.coderising0226.array;

import static org.junit.Assert.*;

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

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};

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

int[] c = new int[0];
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 = null;
int[] e = myArray.removeZero(d);
assertNull(e);

}

@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 = null;
int[] b4 = null;
int[] newArray4 = myArray.merge(a4, b4);
assertNull(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);

int[] c = null;
int[] newArray1 = myArray.grow(c, 3);
assertNull(newArray1);

// size < 0 抛出异常
expectedEx.expect(Exception.class);
myArray.grow(a, -3);
}

@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
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，返回空字符串
int[] Array2 = new int[0];
String s4 = myArray.join(Array2, "-");
String s5 = "";
assertEquals(s4, s5);
}

}


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