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haolipenghaolipeng
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Merge pull request onlyliuxin#7 from yangdd1205/master
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2 parents c399cd9 + 9c08fc8 commit a537538

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‎group18/1049843090/.classpath

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<?xml version="1.0" encoding="UTF-8"?>
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<classpath>
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<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
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<classpathentry kind="src" path="src"/>
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<classpathentry kind="src" path="test"/>
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<classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/.jar"/>
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<classpathentry kind="lib" path="lib/junit-4.12.jar"/>
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<classpathentry kind="lib" path="lib/hamcrest-core-1.3.jar"/>
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<classpathentry kind="output" path="out/production/1049843090"/>
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</classpath>

‎group18/1049843090/.gitignore

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*.idea
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*.iml
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*.eml
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.settings/
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target/
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build/
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out/

‎group18/1049843090/.project

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<?xml version="1.0" encoding="UTF-8"?>
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<projectDescription>
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<name>1049843090</name>
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<comment/>
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<projects/>
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<buildSpec>
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<buildCommand>
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<name>org.eclipse.jdt.core.javabuilder</name>
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<arguments/>
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</buildCommand>
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</buildSpec>
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<natures>
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<nature>org.eclipse.jdt.core.javanature</nature>
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</natures>
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</projectDescription>

‎group18/1049843090/src/com/coderising/array/ArrayUtil.java

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package com.coderising.array;
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import com.coding.basic.Queue;
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import com.coding.basic.Stack;
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public class ArrayUtil {
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/**
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* 给定一个整形数组a , 对该数组的值进行置换
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* 例如： a = [7, 9 , 30, 3] , 置换后为 [3, 30, 9,7]
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* 如果 a = [7, 9, 30, 3, 4] , 置换后为 [4,3, 30 , 9,7]
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*
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* @param origin
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* @return
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*/
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public void reverseArray(int[] origin) {
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if (isEmptyOrNull(origin)) {
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return;
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}
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//solution 1 move element
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//for (int i = 0; i <= origin.length >> 2; i++) {
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// int temp = origin[i];
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// origin[i] = origin[origin.length - 1 - i];
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// origin[origin.length - 1 - i] = temp;
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//}
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//solution 2 use Stack
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Stack<Integer> stack = new Stack<>();
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for (int i : origin) {
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stack.push(i);
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}
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for (int i = 0; i < origin.length; i++) {
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origin[i]=stack.pop();
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}
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}
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/**
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* 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}
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* 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：
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* {1,3,4,5,6,6,5,4,7,6,7,5}
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*
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* @param oldArray
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* @return
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*/
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public int[] removeZero(int[] oldArray) {
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if (isEmptyOrNull(oldArray)) {
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return null;
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}
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//solution 1 use Queue OR Stack
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//Queue<Integer> queue = new Queue<>();
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//for (int i : oldArray) {
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// if (i != 0) {
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// queue.enQueue(i);
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// }
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//}
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//int[] newArray = new int[queue.size()];
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//for (int i = 0; i < newArray.length; i++) {
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// newArray[i] = queue.deQueue();
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//}
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//return newArray;
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//solution 2 use Array
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int[] tempArray = new int[oldArray.length];
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int index = 0;
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for (int i = 0; i < oldArray.length; i++) {
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if (oldArray[i] != 0) {
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tempArray[index++] = oldArray[i];
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}
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}
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int[] newArray = new int[index];
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System.arraycopy(tempArray,0,newArray,0,index);
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return newArray;
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}
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/**
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* 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
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* 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
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*
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* @param array1
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* @param array2
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* @return
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*/
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public int[] merge(int[] array1, int[] array2) {
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return null;
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}
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/**
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* 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
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* 注意，老数组的元素在新数组中需要保持
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* 例如 oldArray = [2,3,6] , size = 3,则返回的新数组为
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* [2,3,6,0,0,0]
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*
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* @param oldArray
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* @param size
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* @return
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*/
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public int[] grow(int[] oldArray, int size) {
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if (isEmptyOrNull(oldArray)) {
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return null;
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}
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int[] newArray = new int[oldArray.length + size];
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//solution 1 use System.arraycopy
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//System.arraycopy(oldArray,0,newArray,0, oldArray.length);
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//solution 2 use loop
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for (int i = 0; i < oldArray.length; i++) {
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newArray[i] = oldArray[i];
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}
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return newArray;
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}
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/**
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* 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
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* 例如， max = 15 , 则返回的数组应该为 [1，1，2，3，5，8，13]
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* max = 1, 则返回空数组 []
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*
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* @param max
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* @return
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*/
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public int[] fibonacci(int max) {
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return null;
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}
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/**
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* 返回小于给定最大值max的所有素数数组
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* 例如max = 23, 返回的数组为[2,3,5,7,11,13,17,19]
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*
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* @param max
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* @return
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*/
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public int[] getPrimes(int max) {
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return null;
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}
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/**
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* 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
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* 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
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*
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* @param max
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* @return
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*/
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public int[] getPerfectNumbers(int max) {
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return null;
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}
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/**
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* 用seperator 把数组 array给连接起来
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* 例如array= [3,8,9], seperator = "-"
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* 则返回值为"3-8-9"
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*
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* @param array
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* @param seperator 分隔符
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* @return
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*/
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public String join(int[] array, String seperator) {
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if (isEmptyOrNull(array)) {
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return "";
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}
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if (array.length < 2) {
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return array[0] + "";
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}
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StringBuffer stringBuffer = new StringBuffer();
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for (int i = 0; i < array.length - 1; i++) {
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stringBuffer.append(array[i] + seperator);
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}
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stringBuffer.append(array[array.length - 1]);
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return stringBuffer.toString();
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}
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/**
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* 检查数组是否为空或者为null
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*
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* @param array
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* @return
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*/
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private boolean isEmptyOrNull(int[] array) {
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if (array == null || array.length == 0) {
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return true;
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}
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return false;
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}
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public static void main(String[] args) {
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int[] a = {7,9,5};
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ArrayUtil arrayUtil = new ArrayUtil();
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arrayUtil.reverseArray(a);
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for (int i : a) {
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System.out.println(i);
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}
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}
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}

‎group18/1049843090/src/com/coding/basic/ArrayList.java

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package com.coding.basic;
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import java.util.Arrays;
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/**
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* A Simple ArrayList
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*/
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public class ArrayList<E> implements List<E> {
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/**
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* 当前list的元素个数
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*/
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private int size;
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/**
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* 默认数组大小
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*/
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private static final int DEFAULT_CAPACITY = 10;
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/**
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* 存储元素的数组
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*/
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private Object[] elementData;
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/**
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* 追加一个元素
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*
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* @param e
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*/
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public void add(E e) {
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grow();
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elementData[size++] = e;
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}
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private void grow() {
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if (elementData.length == size) {
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elementData = Arrays.copyOf(elementData, size + 10);
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}
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}
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/**
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* 插入一个元素到指定位置
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*
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* @param index
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* @param e
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*/
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public void add(int index, E e) {
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if (index < 0 || index > size) {
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throw new IndexOutOfBoundsException("下标越界");
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}
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grow();
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int movedNum = size - index;
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if (movedNum > 0) {
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System.arraycopy(elementData, index, elementData, index + 1, movedNum);
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}
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elementData[index] = e;
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size++;
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}
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/**
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* 获取指定位置的元素
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*
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* @param index
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* @return
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*/
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public E get(int index) {
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checkIndex(index);
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return getElement(index);
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}
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/**
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* 删除指定位置的元素
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*
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* @param index
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* @return
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*/
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public E remove(int index) {
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checkIndex(index);
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E delEle = getElement(index);
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int movedNum = size - index - 1;//是不是最后一个元素
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if (movedNum > 0) {
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System.arraycopy(elementData, index + 1, elementData, index, movedNum);
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}
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elementData[--size] = null;
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return delEle;
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}
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private void checkIndex(int index) {
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if (index < 0 || index >= size) {
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throw new IndexOutOfBoundsException("下标越界");
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}
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}
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private E getElement(int index) {
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return (E) elementData[index];
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}
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/**
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* list中元素的个数
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*
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* @return
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*/
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public int size() {
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return this.size;
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}
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public ArrayList() {
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this.elementData = new Object[DEFAULT_CAPACITY];
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}
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public Iterator<E> iterator() {
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return new ArrayListIterator();
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}
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private class ArrayListIterator<E> implements Iterator<E> {
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private int cursor;//游标
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private int lastRet = -1;//可被删除元素下标
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@Override
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public boolean hasNext() {
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return cursor != size;
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}
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@Override
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public E next() {
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int i = cursor;
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cursor++;
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return (E) elementData[lastRet = i];
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}
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@Override
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public void remove() {
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if (lastRet < 0) {
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throw new IllegalStateException();
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}
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cursor = lastRet;//游标等于当前删除元素的下标 或者 cursor--;
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ArrayList.this.remove(lastRet);
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lastRet = -1;//重置可删元素下标
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}
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}
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}

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