Java 实现的一个链表翻转示例
前期准备工作（包括相关工具或所使用的原料等）IntelliJ IDEA 详细的操作方法或具体步骤
这两天在研究JDK1.6 HashMap的源码，看着链表比较有趣，就参照HashMap resize时的transfer方法写了一个链表翻转的Demo
先看看输出的效果：
entry:E1-key=E1-value
entry.next:E2-key=E2-value
===================华丽的分隔线===================
entry:E2-key=E2-value
entry.next:E1-key=E1-value
来看看对Node节点class的定义
此处继承了Map.Entry的结构
static class Entry
final K key;
V value;
Entry
final int hash;
/**
* Creates new entry.
*/
Entry(int h, K k, V v, Entry
value=v;
next=n;
key=k;
hash=h;
}
public final K getKey() {
return key;
}
public final V getValue() {
return value;
}
public final V setValue(V newValue) {
V oldValue=value;
value=newValue;
return oldValue;
}
public final boolean equals(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e=(Map.Entry) o;
Object k1=getKey();
Object k2=e.getKey();
if (k1==k2 || (k1 !=null && k1.equals(k2))) {
Object v1=getValue();
Object v2=e.getValue();
if (v1==v2 || (v1 !=null && v1.equals(v2)))
return true;
}
return false;
} public final int hashCode() {
return (key==null ? 0 : key.hashCode()) ^ (value==null ? 0 : value.hashCode());
} public final String toString() {
return getKey() + "=" + getValue();
}
/**
* This method is invoked whenever the value in an entry is
* overwritten by an invocation of put(k,v) for a key k that's already
* in the HashMap.
*/
void recordAccess(HashMap
}
/**
* This method is invoked whenever the entry is
* removed from the table.
*/
void recordRemoval(HashMap
}
}
反转链表的代码：
void transfer(Entry[] src, Entry[] newTable) {
for (int j=0; j < src.length; j++) {
Entry
if (e !=null) {
src[j]=null;
do {
Entry
int i=0;
e.next=newTable[i];
newTable[i]=e;
e=next;
} while (e !=null);
}
}
}
解析一下反转链表的逻辑
看看main方法
public static void main(String[] args) {
ReverseLinkedListDemo
Entry[] newTable=new Entry[1];
Entry
Entry
Entry[] src=http://jingyan.baidu.com/article/{E1};
reverseLinkedListDemo.printLinkedEntry(src);
reverseLinkedListDemo.transfer(src, newTable);
System.out.println("===================华丽的分隔线===================");
reverseLinkedListDemo.printLinkedEntry(newTable);
}
执行下，看看结果
entry:E1-key=E1-value
entry.next:E2-key=E2-value
===================华丽的分隔线===================
entry:E2-key=E2-value
entry.next:E1-key=E1-value
粘一下完整的代码：
Code:
package chapter4;
import java.util.HashMap;
import java.util.Map;
public class ReverseLinkedListDemo
public static void main(String[] args) {
ReverseLinkedListDemo
Entry[] newTable=new Entry[1];
Entry
Entry
Entry[] src=http://jingyan.baidu.com/article/{E1};
reverseLinkedListDemo.printLinkedEntry(src);
reverseLinkedListDemo.transfer(src, newTable);
System.out.println("===================华丽的分隔线===================");
reverseLinkedListDemo.printLinkedEntry(newTable);
} private void printLinkedEntry(Entry[] newTable) {
for (Entry entry : newTable) {
System.out.println("entry:" + entry);
if (entry !=null && entry.next !=null) {
System.out.println("entry.next:" + entry.next);
}
}
}
/**
* Transfers all entries from current table to newTable.
*/
void transfer(Entry[] src, Entry[] newTable) {
for (int j=0; j < src.length; j++) {
Entry
if (e !=null) {
src[j]=null;
do {
Entry
int i=0;
e.next=newTable[i];
newTable[i]=e;
e=next;
} while (e !=null);
}
}
}
static class Entry
final K key;
V value;
Entry
final int hash;
/**
* Creates new entry.
*/
Entry(int h, K k, V v, Entry
value=v;
next=n;
key=k;
hash=h;
} public final K getKey() {
return key;
}
public final V getValue() {
return value;
}
public final V setValue(V newValue) {
V oldValue=value;
value=newValue;
return oldValue;
}
public final boolean equals(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e=(Map.Entry) o;
Object k1=getKey();
Object k2=e.getKey();
if (k1==k2 || (k1 !=null && k1.equals(k2))) {
Object v1=getValue();
Object v2=e.getValue();
if (v1==v2 || (v1 !=null && v1.equals(v2)))
return true;
}
return false;
} public final int hashCode() {
return (key==null ? 0 : key.hashCode()) ^ (value==null ? 0 : value.hashCode());
} public final String toString() {
return getKey() + "=" + getValue();
} /**
* This method is invoked whenever the value in an entry is
* overwritten by an invocation of put(k,v) for a key k that's already
* in the HashMap.
*/
void recordAccess(HashMap
}
/**
* This method is invoked whenever the entry is
* removed from the table.
*/
void recordRemoval(HashMap
}
}
}
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