A brief analysis of the principle and simple implementation of linear tables

1. Linear table

Principle: a finite sequence of zero or more similar data elements

Principle:

Features:

1. Orderliness

2. Finiteness

3. Elements of the same type

4. The first element has no predecessor, and the last An element has no successor, and the middle element has a predecessor and a successor

Linear list is a logical data structure, and there are generally two physical implementations: sequential implementation and linked list implementation

2. Array-based linear table sequence implementation

Principle: Use a storage unit with a continuous address to store linear table data elements in sequence.

Principle diagram:

Algorithm principle:

1. Initialize a fixed-length array space elementData[], size storage length storage Elements

2. Quickly access elements through indexes

3. Insertion and deletion of elements through array copy

Summary:

1. No need Add additional storage space to express the logical relationship between elements in the table

2. You can quickly access elements at any position in the table

3. Insertion and deletion require array copying (i.e. Movement of a large number of elements)

4. When the length of the linear table changes greatly, frequent expansion is required and storage space fragmentation occurs

Implementation code:

Interface definition:

 1 package online.jfree.base; 2  3 /** 4  * author : Guo LiXiao 5  * date : 2017-6-14  11:46 6  */ 7  8 public interface LineList <E>{ 9 10     /**11      * lineList 是否为空12      * @return13      */14     boolean isEmpty();15 16     /**17      * 清空 lineList18      */19     void clear();20 21     /**22      * 获取指定位置元素23      * @param index24      * @return25      */26     E get(int index);27 28     /**29      * 获取元素第一次出现的位置30      * @param e31      * @return32      */33     int indexOf(E e);34 35     /**36      * 判断 lineList是否包含指定元素37      * @param e38      * @return39      */40     boolean contains(E e);41 42     /**43      * 设置指定位置数据，如数据已存在 则覆盖原数据44      * @param index45      * @param e46      * @return47      */48     E set(int index, E e);49 50     /**51      * 移除指定位置元素52      * @param index53      * @return54      */55     E remove(int index);56 57     /**58      * 在lineList结尾插入元素59      * @param e60      * @return61      */62     E add(E e);63 64     /**65      * 在index后面插入元素66      * @param index67      * @param e68      * @return69      */70     E add(int index, E e);71 72     /**73      * 返回lineList长度74      * @return75      */76     int size();77 78 79 80 }

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Algorithm implementation:

  1 package online.jfree.base;  2   3 /**  4  * author : Guo LiXiao  5  * date : 2017-6-15  13:44  6  */  7   8 public class OrderedLineList<E> implements LineList<E> {  9  10     private static final int INIT_CAPACITY = 10; 11  12     private transient E[] elementData; 13  14     private transient int elementLength; 15  16     private int size; 17  18     public OrderedLineList() { 19         this(0); 20     } 21  22     public OrderedLineList(int initCapacity) { 23         init(initCapacity); 24     } 25  26     private void init(int initCapacity) { 27         if (initCapacity >= 0) { 28             this.elementData = (E[]) new Object[initCapacity]; 29             this.elementLength = initCapacity; 30         } else { 31             throw new IllegalArgumentException("Illegal Capacity: " + 32                     initCapacity); 33         } 34         this.size = 0; 35     } 36  37     /** 38      * 扩容 39      */ 40     private void dilatation() { 41         int oldCapacity = this.elementLength; 42         int newCapacity = oldCapacity; 43         if (oldCapacity <= this.size) { 44             newCapacity = oldCapacity + INIT_CAPACITY; 45         }else if(oldCapacity - INIT_CAPACITY > this.size){ 46             newCapacity = oldCapacity - INIT_CAPACITY; 47         } 48         if (oldCapacity != newCapacity){ 49             E[] newElementData = (E[]) new Object[newCapacity]; 50             System.arraycopy(elementData, 0, newElementData, 0, oldCapacity); 51             this.elementLength = newCapacity; 52             this.elementData = newElementData; 53         } 54     } 55  56     /** 57      * 校验列表索引越界 58      * @param index 59      */ 60     private void checkCapacity(int index){ 61         if (index > this.size - 1 || index < 0) 62             throw new IndexOutOfBoundsException(new StringBuffer("[index : ").append(index).append("] , [size : ").append(size).append("] ").toString()); 63     } 64  65     @Override 66     public boolean isEmpty() { 67         return this.size == 0; 68     } 69  70     @Override 71     public void clear() { 72         this.init(0); 73     } 74  75     @Override 76     public E get(int index) { 77         this.checkCapacity(index); 78         return this.elementData[index]; 79     } 80  81     @Override 82     public int indexOf(E e) { 83         for (int i = 0; i < this.size; i++){ 84             if (e == null && elementData[i] == null || e.equals(elementData[i])){ 85                 return i; 86             } 87         } 88         return -1; 89     } 90  91     @Override 92     public boolean contains(E e) { 93         return this.indexOf(e) > 0; 94     } 95  96     @Override 97     public E set(int index, E e) { 98         this.checkCapacity(index); 99         this.dilatation();100         E oldElement = this.elementData[index];101         this.elementData[index] = e;102         return oldElement;103     }104 105     @Override106     public E remove(int index) {107         this.dilatation();108         E e = elementData[index];109         if (index == size - 1) elementData[index] = null;110         else {111             int length = size - index - 1;112             System.arraycopy(elementData, index + 1, elementData, index, length);113         }114         size --;115         return e;116     }117 118     @Override119     public E add(E e) {120         return this.add(size, e);121     }122 123     @Override124     public E add(int index, E e) {125         this.dilatation();126         if (index == size) elementData[index] = e;127         else {128             index++;129             int lastLength = size - index;130             E[] lastElementData = (E[]) new Object[lastLength];131             System.arraycopy(elementData, index, lastElementData, 0, lastLength);132             elementData[index] = e;133             System.arraycopy(lastElementData, 0, elementData, index + 1, lastLength);134         }135         size ++ ;136         return e;137     }138 139     @Override140     public int size() {141         return this.size;142     }143 144 }

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