###1. 无序数组

package com.fantj.dataStruct.array;/*** Created by Fant.J.* 2017/12/20 18:16*/
public class MyArray {private long[] arr;//表示有效数据的长度private int elements;public MyArray() {arr = new long[50];}public MyArray(int maxsize) {arr = new long[maxsize];}/*** 添加数据*/public void insert(long value){arr[elements] = value;elements++;}/*** 显示数据*/public void display(){System.out.print("[");for (int i = 0;i < elements;i++){System.out.print(arr[i]+" ");}System.out.print("]");}/*** 查找数据(根据元素查找)*/public int search(long value){int i;for (i = 0;i < elements;i++){if (value == arr[i]){break;}}//是否查到最后一个了if (i == elements){return -1;  //查找不到}else {return i;}}/*** 根据索引查找*/public long get(int index){if (index >= elements || index < 0){throw new ArrayIndexOutOfBoundsException();}else {return arr[index];}}/*** 删除数据*/public void delete(int index){if (index >= elements || index < 0){throw new ArrayIndexOutOfBoundsException();}else {for (int i = index;i < elements;i++){arr[index] = arr[index+1];}elements--;}}/*** 更新数据*/public void update(int index,long newvalue){if (index >= elements || index < 0){throw new ArrayIndexOutOfBoundsException();}else {arr[index] = newvalue;}}
}
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###2. 有序数组(只在添加数据的时候做了改动)

    /*** 添加数据*/public void insert(long value){int i;for (i = 0;i<elements;i++){if (arr[i] > value){break;}}for (int j = elements;j>i;j--){arr[j] = arr[j-1];}arr[i] = value;elements++;}
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###3.二分法查找(前提是有序数组)

    /*** 二分法查找*/public int binarySearch(long value){int pow = elements;int low = 0;int middle;while (true){middle = (pow+low)/2;if (arr[middle] == value){return middle;}else {if (arr[middle]>value){pow = middle - 1;  //如果数组中间的值比value大，middle-1}else {low = middle + 1; //如果小，最小届加一}}}}
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