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package com.wpr.collection; import java.util.LinkedList; import java.util.List; public class HashTable<AnyType> { private static final int DEFAULT_TABLE_SIZE = 101; private List<AnyType>[] theList; private int curSize; public HashTable() { this(DEFAULT_TABLE_SIZE); } public HashTable(int size) { //构造一个质数长度的链表 this.theList = new LinkedList[nextPrime(size)]; for(int i=0;i<theList.length;i++){ theList[i]= new LinkedList<>(); } } /** * 插入,如果元素已经存在,直接返回 * @param x */ public void insert(AnyType x){ List<AnyType> temp = theList[myHast(x)]; if(!temp.contains(x)){ temp.add(x); if(++curSize>theList.length) reHash(); } } /** * 表的size太小,数据的长度和表长相等时重新调整表长,装填因子为1 */ private void reHash() { List<AnyType>[] old = theList; theList = new LinkedList[theList.length*2]; //更新hashTable for(int i=0;i<theList.length;i++) theList[i]=new LinkedList<>(); curSize = 0; for(int i=0;i<old.length;i++){ for(AnyType x:old[i]) insert(x); } } public void clear(){ for(List l:theList){ l.clear(); } } public void remove(AnyType x){ List<AnyType> temp = theList[myHast(x)]; if(temp.contains(x)){ temp.remove(x); curSize--; } } public boolean contain(AnyType x){ List<AnyType> temp = theList[myHast(x)]; return temp.contains(x); } /** * 计算数据的hash值 * @param x * @return */ private int myHast(AnyType x) { int hashValue = x.hashCode(); hashValue%=theList.length; if(hashValue<0) hashValue+=theList.length; return hashValue; } /** * 返回一个比size大的质数 * @param size * @return */ private int nextPrime(int size) { if(size%2==0) size++; while(!isPrime(size)){ size +=2; } return 0; } /** * 判断size是否为质数 * @param size * @return */ private boolean isPrime(int size) { if(size%2==0||size==1) return false; if(size==2 || size==3) return true; for(int i=3;i<Math.sqrt(size);i+=2){ if(size%i==0) return false; } return true; } }
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原文地址:http://www.cnblogs.com/kakaxisir/p/4316246.html