数据结构java描述

接口

package myjava;

public interface Stack {
    int getSize();
    boolean isEmpty();
    void push(E e);
    E pop();
    E peek();
}

  1. 队列
package myjava;

public interface Queue {
    int getSize();
    boolean isEmpty();
    E dequeue();
    void enqueue(E e);
    E getFront();
}

  1. 集合
package myjava;

public interface Set {
    void add(E e);
    void remove(E e);
    boolean contains(E e);
    int getSize();
    boolean isEmpty();
}

  1. 并查集
package myjava;

public interface UnionFind {
    int getSize();
    boolean isConnected(int p, int q);
    void unionElements(int p, int q);
}

  1. 映射
package myjava;

public interface Map {
    void add(K key, V value); // 添加
    void set(K key, V newValue); // 更新
    V remove(K key); // 删除
    V get(K key); // 得到为key 的值
    boolean contains(K key); // 是否包含元素
    boolean isEmpty(); // 是否空
    int getSize(); // 元素个数
}






数组

// 数组
package myjava;

public class Array {
    private E[] data;
     private int size;
     
     public Array(int capacity) {
         data = (E[])(new Object[capacity]);
         size = 0;
     }
     public Array() {
         this(10);
     }
     public Array(E[] arr) {
         data = (E[])(new Object[arr.length]);
         for (int i=0; i= 0 && index <= size) {
            for (int i=size-1; i>=index; i--) {
                data[i+1] = data[i];
            }
            data[index] = val;
            size++;
         }
     }
     private void resize(int capacity) { // 动态扩容数组容量
         E[] newData = (E[])new Object[capacity];
         for (int i=0; i= size) {
             throw new IllegalArgumentException("index is invalid");
         }
         return data[index];
     }
     // 更新某个位置的元素
//     @param{int}index 索引
//     @param{E}val 值
     public void set(int index, E val) { 
         if (index < 0 || index >= size) {
             throw new IllegalArgumentException("index is invalid");
         }
         data[index] = val;
     }
     public boolean contains(E val) { // 是否包含某个元素
         for (int i=0; i= size) {
             throw new IllegalArgumentException("index is invalid");
         }
         if (size == data.length / 2) { // 动态减少数组容量
             resize(data.length/2);
         }
         E ret = data[index];
         for (int i=index; i= size || j<0 || j>= size) {
             throw new ArrayIndexOutOfBoundsException("index is illegal");
         }
         E e = data[i];
         data[i] = data[j];
         data[j] = e;
     }
     @Override
     public String toString() {
         StringBuilder res = new StringBuilder();
         res.append(String.format("Array: size=%d, capacity=%d", size, data.length));
         res.append("[");
         for (int i=0; i






链表

package myjava;

public class LinkedList {
    private class Node { // 链表节点
        private E e;
        private Node next;

        public Node(E e, Node next) {
            this.e = e;
            this.next = next;
        }

        public Node(E e) {
            this(e, null);
        }

        @Override
        public String toString() {
            return e.toString();
        }
    }

    private Node dummyhead;// 虚拟头结点,方便插入动作
    private int size;

    public LinkedList(E e) {
        dummyhead = new Node(null, null);
        dummyhead.next = new Node(e);
        size = 1;
    }

    public LinkedList() {
        dummyhead = new Node(null, null);
        size = 0;
    }

    public int getSize() {
        return size;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    // 插入元素
//  @param{int}index 位置
//  @param{E}e 元素
    public void add(int index, E e) {
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("index is invalid");
        }
        Node prev = dummyhead;
        Node node = new Node(e);
        for (int i = 0; i < index; i++) {
            prev = prev.next;
        }
        prev.next = new Node(e, prev.next);
        size++;
    }
    public void addFirst(E e) {
        add(0, e);
    }
    public void addLast(E e) {
        add(size, e);
    }
    public Node get(int index) { // 得到指定位置元素
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("index is invalid");
        }
        Node cur = dummyhead.next;
        for (int i=0; i= size) {
            throw new IllegalArgumentException("index is invalid");
        }
        Node cur = dummyhead.next;
        for (int i=0; i= size) {
            throw new IllegalArgumentException("index is invalid");
        }
        Node prev = dummyhead;
        for (int i=0; i");
        }
        res.append("NULL");
        return res.toString();
    }
}






  1. 数组实现
package myjava;

public class ArrayStack implements Stack {
    Array array;
    public ArrayStack(int capacity) {
        array = new Array<>(capacity);
    }
    public ArrayStack() {
        array = new Array<>();
    }
    @Override
    public int getSize() {
        return array.getSize();
    }
    @Override
    public boolean isEmpty() {
        return array.isEmpty();
    }
    public int getCapacity() {
        return array.getCapacity();
    }
    public void push(E e) { // 入栈
        array.addLast(e);
    }
    public E pop() {  // 出栈
        return array.removeLast();
    }
    public E peek() { // 栈顶元素 return{E}
        return array.get(array.getSize()-1);
    }
    @Override
    public String toString() {
        int size = array.getSize();
        StringBuilder res = new StringBuilder();
        res.append("Stack: [");
        for (int i=0; i>");
        return res.toString();
    }
}

  1. 链表实现
package myjava;

public class LinkedListQueue implements Queue {
   private class Node {
       private E e;
       private Node next;

       public Node(E e, Node next) {
           this.e = e;
           this.next = next;
       }

       public Node(E e) {
           this(e, null);
       }

       @Override
       public String toString() {
           return e.toString();
       }
   }
   private Node head, tail;
   private int size;
   public LinkedListQueue() {
       head = null;
       tail = null;
       size = 0;
   }
   public int getSize() {
       return size;
   }
   public boolean isEmpty() {
       return size == 0;
   }
   public void enqueue(E e) {
       if (tail == null) {
           head = new Node(e);
           tail = head;
       } else {
           tail.next = new Node(e);
           tail = tail.next;
       }
       size++;
   }
   public E dequeue() {
       if (isEmpty()) {
           return null;
       }
       Node retNode = head;
       head = head.next;
       retNode.next = null;
       if (head == null) {
           tail = null;
       }
       size--;
       return (E)retNode;
   }
   public E getFront() {
       if (isEmpty()) { return null; }
       return (E)head.e;
   }
   @Override
   public String toString() {
       StringBuilder res = new StringBuilder();
       Node current = head;
       res.append("Queue: Top ");
       
       while (current != null) {
           res.append(current);
           current = current.next;
           res.append("->");
       }
       res.append("NULL");
       return res.toString();
   }
}






队列

  1. 数组实现
package myjava;

public class ArrayQueue implements Queue {
   Array array;
   public ArrayQueue(int capacity) {
       array = new Array<>(capacity);
   }
   public ArrayQueue() {
       array = new Array<>();
   }
   @Override
   public int getSize() {
       return array.getSize();
   }
   @Override
   public boolean isEmpty() {
       return array.isEmpty();
   }
   @Override
   public void enqueue(E e) { // 进队
       array.addLast(e);
   }
   @Override
   public E dequeue() { // 出队 return{E}
       return array.removeFirst();
   }
   @Override
   public E getFront() {
       return array.get(0);
   }
   @Override
   public String toString() {
       StringBuilder res = new StringBuilder();
       int size = array.getSize();
       res.append("Queue: << [");
       for (int i=0; i
  1. 链表实现
package myjava;

public class LinkedListQueue implements Queue {
    private class Node {
        private E e;
        private Node next;

        public Node(E e, Node next) {
            this.e = e;
            this.next = next;
        }

        public Node(E e) {
            this(e, null);
        }

        @Override
        public String toString() {
            return e.toString();
        }
    }
    private Node head, tail;
    private int size;
    public LinkedListQueue() {
        head = null;
        tail = null;
        size = 0;
    }
    public int getSize() {
        return size;
    }
    public boolean isEmpty() {
        return size == 0;
    }
    public void enqueue(E e) {
        if (tail == null) {
            head = new Node(e);
            tail = head;
        } else {
            tail.next = new Node(e);
            tail = tail.next;
        }
        size++;
    }
    public E dequeue() {
        if (isEmpty()) {
            return null;
        }
        Node retNode = head;
        head = head.next;
        retNode.next = null;
        if (head == null) {
            tail = null;
        }
        size--;
        return (E)retNode;
    }
    public E getFront() {
        if (isEmpty()) { return null; }
        return (E)head.e;
    }
    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        Node current = head;
        res.append("Queue: Top ");
        
        while (current != null) {
            res.append(current);
            current = current.next;
            res.append("->");
        }
        res.append("NULL");
        return res.toString();
    }
}







二分搜索树

package myjava;
import java.util.Queue;
import java.util.LinkedList;

public class BST> {
    private class Node {
        public E e;
        public Node left, right;
        public Node(E e) {
            this.e = e;
            left = null;
            right = null;
        }
    }
    private Node root;
    private int size;
    public BST() {
        root = null;
        size = 0;
    }
    public int getSize() {
        return size;
    }
    public boolean isEmpty() {
        return size == 0;
    }
    public void add(E e) {
        if (root == null) {
            root = new Node(e);
            size++;
        } else {
            root = add(root, e);
        }
    }
    private Node add(Node node, E e) { // 添加
        if (node == null) {
            size++;
            return new Node(e);
        }
        if (e.compareTo(node.e) < 0) {
            node.left = add(node.left, e);
        } else if (e.compareTo(node.e) > 0) {
            node.right = add(node.right, e);
        }
        return node;
    }
    public boolean contains(E e) { // 是否包含
        return contains(root, e);
    }
    private boolean contains(Node node, E e) {
        if (node == null) {
            return false;
        }
        if (e.compareTo(node.e) == 0) {
            return true;
        } else if (e.compareTo(node.e) < 0) {
            return contains(node.left, e);
        } else {
            return contains(node.right, e);
        }
    }
    public void preOrder() { // 前序遍历
        preOrder(root);
    }
    private void preOrder(Node node) {
        if (node == null) {return ;}
        
        System.out.println(node.e);
        preOrder(node.left);
        preOrder(node.right);
    }
    public void inOrder() {// 中序遍历
        inOrder(root);
    }
    private void inOrder(Node node) {
        if (node == null) {return ;}
        
        preOrder(node.left);
        System.out.println(node.e);
        preOrder(node.right);
    }
    public void postOrder() { // 后序遍历
        postOrder(root);
    }
    private void postOrder(Node node) {
        if (node == null) {return ;}
        
        preOrder(node.left);
        preOrder(node.right);
        System.out.println(node.e);
    }
    public void levelOrder() { // 层次遍历
        Queue queue = new LinkedList<>();
        queue.add(root);
        while (!queue.isEmpty()) {
            Node cur = queue.remove();
            System.out.println(cur.e);
            if (cur.left != null) {
                queue.add(cur.left);
            }
            if (cur.right != null) {
                queue.add(cur.right);
            }
        }
    }
    public Node minimum() { // 得到最小值
        if (root == null) {return null;}
        return minimum(root);
    }
    private Node minimum(Node node) {
        if (node.left == null) {
            return node;
        }
        return minimum(node.left);
    }
    public Node maxmum() { // 得到最大值
        if (root == null) {return null;}
        return maxmum(root);
    }
    private Node maxmum(Node node) {
        if (node.right == null) {
            return node;
        }
        return maxmum(node.right);
    }
    public Node removeMin() {
        Node cur = minimum();
        root = removeMin(root);
        return cur;
    }
    private Node removeMin(Node node) {
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size--;
            return rightNode;
        }
        node.left = removeMin(node.left);
        return node;
    }
    public Node removeMax() {
        Node cur = maxmum();
        root = removeMax(root);
        return cur;
    }
    private Node removeMax(Node node) {
        if (node.right == null) {
            Node leftNode = node.left;
            node.left = null;
            size--;
            return leftNode;
        }
        node.right = removeMax(node.right);
        return node;
    }
    public void remove(E e) {
        root = remove(root, e);
    }
    private Node remove(Node node, E e) {
        if (node == null) {
            return null;
        }
        if (e.compareTo(node.e) < 0) {
            node.left = remove(node.left, e);
            return node;
        } else if (e.compareTo(node.e) > 0) {
            node.right = remove(node.right, e);
            return node;
        } else { // 匹配到
            if (node.left == null) {
                Node rightNode = node.right;
                node.right = null;
                size--;
                return rightNode;
            }
            if (node.right == null) {
                Node leftNode = node.left;
                node.left = null;
                size--;
                return leftNode;
            }
            // 两边都有子结点
            Node successor = minimum(node.right);
            successor.right = removeMin(node.right);
            successor.left = node.left;
            return successor;
        }
    }
    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        generateBSTString(root, 0, res);
        return res.toString();
    }
    private void generateBSTString(Node node, int depth, StringBuilder res) {
        if (node == null) {
            res.append(generateDepthString(depth)+"nlll\n");
            return ;
        }
        res.append(generateDepthString(depth)+node.e+"\n");
        generateBSTString(node.left, depth+1, res);
        generateBSTString(node.right, depth+1, res);
    }
    private String generateDepthString(int depth) {
        StringBuilder res = new StringBuilder();
        for (int i=0; i






集合

  1. 二分搜索树实现
package myjava;

public class BSTSet> implements Set {
   private BST bst;
   public BSTSet() {
       bst = new BST<>();
   }
   @Override
   public void add(E e) {
       bst.add(e);
   }
   @Override
   public void remove(E e) {
       bst.remove(e);
   }
   @Override
   public boolean contains(E e) {
       return bst.contains(e);
   }
   @Override
   public int getSize() {
       return bst.getSize();
   }
   @Override 
   public boolean isEmpty() {
       return bst.isEmpty();
   }
}

  1. 链表实现
package myjava;

public class LinkedListSet> implements Set {
    private LinkedList list;
    LinkedListSet() {
        list = new LinkedList<>();
    }
    @Override
    public int getSize() {
        return list.getSize();
    }
    @Override
    public boolean isEmpty() {
        return list.isEmpty();
    }
    @Override
    public boolean contains(E e) {
        return list.contains(e);
    }
    @Override
    public void add(E e) {
        if (!list.contains(e)) {
            list.addFirst(e);
        }
    }
    @Override
    public void remove(E e) {
        list.removeElement(e);
    }
}






映射

  1. 二分搜索树实现
package myjava;

public class BSTMap, V> implements Map {
    private class Node {
        public K key;
        public V value;
        public Node left, right;
        public Node(K key, V value) {
            this.key = key;
            this.value = value;
            left = null;
            right = null;
        }
    }
    private Node root;
    private int size;
    public BSTMap() {
        this.root = null;
        this.size = 0;
    }
    @Override
    public int getSize() {
        return size;
    }
    @Override
    public boolean isEmpty() {
        return size == 0;
    }
    @Override
    public void add(K key, V value) {
        if (root == null) {
            root = new Node(key, value);
            size++;
        } else {
            root = add(root, key, value);
        }
    }
    private Node add(Node node, K key, V value) { // 添加
        if (node == null) {
            size++;
            return new Node(key, value);
        }
        if (key.compareTo(node.key) < 0) {
            node.left = add(node.left, key, value);
        } else if (key.compareTo(node.key) > 0) {
            node.right = add(node.right, key, value);
        } else {
            node.value = value;
        }
        return node;
    }
    private Node getNode(Node node, K key) {
        if (node == null) {
            return null;
        }
        if (key.compareTo(node.key) == 0) {
            return node;
        } else if (key.compareTo(node.key) < 0) {
            return getNode(node.left, key);
        } else { // >0
            return getNode(node.right, key);
        }
    }
    @Override
    public boolean contains(K key) {
        Node node = getNode(root, key);
        return node != null;
    }
    @Override
    public V get(K key) {
        Node node = getNode(root, key);
        return node != null ? node.value : null;
    }
    @Override
    public void set(K key, V value) {
        Node node = getNode(root, key);
        if (node == null) {
            throw new IllegalArgumentException(key+"doesn't exit!");
        }
        node.value = value;
    }
    @Override
    public V remove(K key) {
        Node node = getNode(root, key);
        if (node != null) {
            root = remove(root, key);
            return node.value;
        }
        return null;
    }
    private Node remove(Node node, K key) {
        if (node == null) {
            return null;
        }
        if (key.compareTo(node.key) < 0) {
            node.left = remove(node.left, key);
            return node;
        } else if (key.compareTo(node.key) > 0) {
            node.right = remove(node.right, key);
            return node;
        } else { // 匹配到
            if (node.left == null) {
                Node rightNode = node.right;
                node.right = null;
                size--;
                return rightNode;
            }
            if (node.right == null) {
                Node leftNode = node.left;
                node.left = null;
                size--;
                return leftNode;
            }
            // 两边都有子结点
            Node successor = minimum(node.right);
            successor.right = removeMin(node.right);
            successor.left = node.left;
            return successor;
        }
    }
    public Node minimum() { // 得到最小值
        if (root == null) {return null;}
        return minimum(root);
    }
    private Node minimum(Node node) {
        if (node.left == null) {
            return node;
        }
        return minimum(node.left);
    }
    public Node removeMin() {
        Node cur = minimum();
        root = removeMin(root);
        return cur;
    }
    private Node removeMin(Node node) { // 删除最小值
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size--;
            return rightNode;
        }
        node.left = removeMin(node.left);
        return node;
    }
}

  1. 链表实现
package myjava;

public class LinkedListMap implements Map {
   private class Node {
       public K key;
       public V value;
       public Node next;
       
       public Node(K key, V value, Node next) {
           this.key = key;
           this.value = value;
           this.next = next;
       }
       public Node(K key) {
           this(key, null, null);
       }
       public Node() {
           this(null, null, null);
       }
   }
   private Node dummyhead;
   private int size;
   public LinkedListMap() {
       this.dummyhead = new Node();
       size = 0;
   }
   @Override
   public int getSize() {
       return size;
   }
   @Override
   public boolean isEmpty() {
       return size == 0;
   }
   private Node getNode(K key) {
       Node cur = dummyhead.next;
       while (cur != null) {
           if (cur.key.equals(key)) {
               return cur;
           }
           cur = cur.next;
       }
       return null;
   }
   @Override
   public boolean contains(K key) {
       return getNode(key) != null;
   }
   @Override
   public V get(K key) {
       Node node = getNode(key);
       return node != null ? node.value : null;
   }
   @Override
   public void add(K key, V value) {
       Node node = getNode(key);
       if (node == null) {
           dummyhead.next = new Node(key, value, dummyhead.next);
       } else {
           node.value = value;
       }
   }
   @Override
   public void set(K key, V value) {
       Node node = getNode(key);
       if (node == null) {
           throw new IllegalArgumentException(key+"doesn't exit!");
       }
       node.value = value;
   }
   @Override
   public V remove(K key) {
       Node prev = dummyhead;
       while (prev != null) {
           if (key.equals(prev.next.key)) {
               break;
           }
           prev = prev.next;
       }
       if (prev.next != null) {
           Node ret = prev.next;
           prev.next = ret.next;
           ret.next = null;
           size--;
           return ret.value;
       }
       return null;
   }
}






最大堆

package myjava;

public class MaxHeap> {
    private Array data;
    public MaxHeap(int capacity) {
        data = new Array<>(capacity);
    }
    public MaxHeap() {
        data = new Array<>();
    }
    public MaxHeap(E[] arr) {
        data = new Array<>(arr);
        for (int i=parent(arr.length-1); i>=0; i--) {
            shiftDown(i);
        }
    }
    public int getSize() {
        return data.getSize();
    }
    public boolean isEmpty() {
        return data.isEmpty();
    }
    private int parent(int index) { // 得到父节点的索引
        if (index == 0) {
            throw new ArrayIndexOutOfBoundsException("index-0 doesn't parent");
        }
        return (index-1)/2;
    }
    private int leftChild(int index) { // 返回左孩子索引
        return index*2+1;
    }
    private int rightChild(int index) { // 返回右孩子索引
        return index*2+2;
    }
    public void add(E e) {
        data.addLast(e);
        shiftUp(getSize()-1);
    }
    private void shiftUp(int k) {
        while (k>0 && data.get(parent(k)).compareTo(data.get(k)) < 0) {
            data.swap(k, parent(k));
            k=parent(k);
        }
    }
    public E findMax() {
        if (data.getSize() == 0) {
            throw new UnsupportedOperationException("heap is empty");
        }
        return data.get(0);
    }
    public E extractMax() {
        E ret = findMax();
        data.swap(0, data.getSize()-1);
        data.removeLast();
        shiftDown(0);
        return ret;
    }
    private void shiftDown(int k) {
        int size = data.getSize();
        while (leftChild(k) < size) {
            int j = leftChild(k);
            if (j+1 < size && data.get(j+1).compareTo(data.get(j))>0) {
                j = rightChild(k);
            }
            if (data.get(k).compareTo(data.get(j)) > 0) {
                break;
            }
            data.swap(k, j);
            k = j;
        }
    }
    public E replace(E e) { // 返回最大元素并放入一个新元素
        E ret = findMax();
        data.set(0, e);
        shiftDown(0);
        return ret;
    }
}






优先队列

package myjava;

public class PriorityQueue> implements Queue {
    private MaxHeap maxHeap;
    public PriorityQueue() {
        maxHeap = new MaxHeap();
    }
    @Override
    public int getSize() {
        return maxHeap.getSize();
    }
    @Override
    public boolean isEmpty() {
        return maxHeap.isEmpty();
    }
    @Override
    public E getFront() {
        return (E) maxHeap.findMax();
    }
    @Override
    public void enqueue(E e) {
        maxHeap.add(e);
    }
    @Override
    public E dequeue() {
        return (E)maxHeap.extractMax();
    }
}






前缀树

package myjava;
import java.util.TreeMap;

public class Trie {
    private class Node {
        public boolean isWord;
        public TreeMap next;
        public Node(boolean isWord) {
            this.isWord = isWord;
            next = new TreeMap<>();
        }
        public Node() {
            this(false);
        }
    }
    private Node root;
    private int size;
    public Trie() {
        root = new Node();
    }
    public void add(String word) { // 添加单词
        Node cur = root;
        for (int i=0; i






并查集

package myjava;

public class ArrayUF implements UnionFind {
    private int[] parent;
    private int[] rank;
    
    public ArrayUF(int size) {
        parent = new int[size];
        rank = new int[size];
        
        for (int i=0; i= parent.length) {
            throw new IllegalArgumentException("p is out of bound");
        }
        while (p != parent[p]) {
            parent[p] = parent[parent[p]]; // 路径压缩,缩短到根节点的距离
            p = parent[p];
        }
        return p;
    }
    @Override
    public boolean isConnected(int p, int q) {
        return find(p) == find(q);
    }
    @Override
    public void unionElements(int p, int q) {
        int pRoot = find(p);
        int qRoot = find(q);
        
        if (pRoot == qRoot) {
            return;
        }
        if (rank[pRoot] < rank[qRoot]) {
            parent[pRoot] = qRoot;
        } else if (rank[pRoot] > rank[qRoot]) {
            parent[qRoot] = pRoot;
        } else {
            parent[qRoot] = pRoot;
            rank[pRoot] += 1;
        }
    }
}






哈希表

package myjava;
import java.util.TreeMap;

public class HashTable {
    private TreeMap[] hashtable;
    private int M;
    private int size;
    
    public HashTable(int M) {
        this.M = M;
        size = 0;
        hashtable = new TreeMap[M];
        for (int i=0; i();
        }
    }
    public HashTable() {
        this(97);
    }
    public int hash(K key) {
        return (key.hashCode() & 0x7ffffff) % M;
    }
    public int getSize() {
        return size;
    }
    public void add(K key, V value) {
        TreeMap map = hashtable[hash(key)];
        if (map.containsKey(key)) {
            map.put(key, value);
        } else {
            map.put(key, value);
            size++;
        }
    }
    public V remove(K key) {
        TreeMap map = hashtable[hash(key)];
        V ret = null;
        if (map.containsKey(key)) {
            ret = map.remove(key);
            size--;
        }
        return ret;
    }
    public void set(K key, V value) {
        TreeMap map = hashtable[hash(key)];
        if (!map.containsKey(key)) {
            throw new IllegalArgumentException(key+"doesn't exist!");
        }
        map.put(key, value);
    }
    public boolean contains(K key) {
        return hashtable[hash(key)].containsKey(key);
    }
    public V get(K key) {
        return hashtable[hash(key)].get(key);
    }
}

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