算法：golang实现arrayList与数组迭代器

本是古典何须时尚 2023-02-15 15:52 105阅读 0赞

> 模拟java中的arraylist

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实现arrayList

package arrayList
    
    import (
    	"errors"
    	"fmt"
    )
    
    type List interface {
        
    	Append(value... interface{
        })(error)
    	Remove(index int)(interface{
        }, error)
    }
    
    // golang的结构体中不可能有默认值
    type ArrayList struct {
        
    	size int
    	elementData []interface{
        }
    }
    
    
    
    func NewArrayList() *ArrayList  {
        
    	list := new(ArrayList)
    	list.size = 0;
    	list.elementData = make([]interface{
        }, 0, 1);
    	return list
    }
    
    func (list *ArrayList)Get(index int) (interface{
        }, error)  {
        
    	// 先检查是不是超出范围
    	if index < 0 || index >= list.size {
        
    		return nil, errors.New("超出索引范围")
    	}
    
    
    	return list.elementData[index], nil
    }
    
    func (list *ArrayList)Set(index int, value interface{
        }) ( error)  {
        
    	// 先检查是不是超出范围
    	if index < 0 || index >= list.size {
        
    		return errors.New("超出索引范围")
    	}
    
    
    	list.elementData[index] = value;
    	return  nil
    }
    
    func (list *ArrayList)Clear() {
        
    	list.elementData = make([]interface{
        }, 0)
    	list.size = 0;
    }
    func (list *ArrayList)ToString() string {
        
    	return fmt.Sprint(list)
    }
    
    func (list *ArrayList) Append(value ...interface{
        }) error {
        
    	// 他会自动扩容
    	for _, v := range value{
        
    		list.elementData = append(list.elementData, v)
    		list.size++;
    	}
    
    	return nil
    }
    
    func (List *ArrayList) Remove(index int) (interface{
        }, error){
        
    	// 先检查是不是超出范围
    	if index < 0 || index >= List.size {
        
    		return nil, errors.New("超出索引范围")
    	}
    
    	oldValue := List.elementData[index];
    
    	//怎么赋值一个数组
    	List.elementData = append(List.elementData[:index], List.elementData[index+1:]...)
    	List.size--;
    
    	return oldValue, nil
    }
    
    func (List *ArrayList) Insert(index int, value interface{
        }) (error){
        
    	// 先检查是不是超出范围
    	if index < 0 || index > List.size {
        
    		return  errors.New("超出索引范围")
    	}
    
    	// 将所有元素后移动一位
    	List.elementData = append(List.elementData, value)
    	List.size++;
    	for i := List.size - 1; i > index ; i-- {
        
    		List.elementData[i] = List.elementData[i-1];
    	}
    	List.elementData[index] = value
    
    
    	return nil
    }

实现数组迭代器

package arrayList
    
    import (
    	"errors"
    )
    
    type Iterator interface {
        
    	HashNext() bool
    	Next() (interface{
        }, error)
    	Remove() (error)
    }
    
    type Iterable interface {
        
    	Iterator() Iterator
    }
    
    type ArraylistIterator struct {
        
    	list *ArrayList
    	cursor int
    	lastRet int;
    }
    
    func (a *ArraylistIterator) Remove() error {
        
    	if a.lastRet == -1 {
        
    		return errors.New("不允许这样使用")
    	}
    
    	_, err := a.list.Remove(a.lastRet)
    	if err != nil {
        
    		 return err
    	}
    	a.cursor = a.lastRet
    	a.lastRet = -1;
    
    	return nil
    }
    
    func (a *ArraylistIterator) HashNext() bool {
        
    	return a.cursor != a.list.size
    }
    
    func (a *ArraylistIterator) Next() (interface{
        }, error) {
        
    	i := a.cursor
    	if i >= a.list.size {
        
    		return nil, errors.New("没有这样的索引")
    	}
    
    	a.cursor = a.cursor + 1;
    	a.lastRet = i
    	return a.list.elementData[a.lastRet], nil;
    }
    
    
    
    func (list *ArrayList) Iterator() Iterator  {
        
    	return &ArraylistIterator{
        
    		list:    list,
    		cursor:  0,
    		lastRet: 0,
    	}
    }

测试

package main
    
    import (
    	"aa/arrayList"
    	"fmt"
    )
    
    
    func main() {
        
    	var list arrayList.List = arrayList.NewArrayList();
    	list.Append(1)
    
    
    	var newArrayList *arrayList.ArrayList = arrayList.NewArrayList()
    
    	for i := 0; i < 10 ; i++ {
        
    		newArrayList.Append(1)
    		newArrayList.Append(2)
    		newArrayList.Append(3);
    		newArrayList.Append(4);
    
    	}
    
    
    	fmt.Println(newArrayList)
    	newArrayList.Set(0, 100)
    	fmt.Println(newArrayList.ToString())
    	newArrayList.Insert(0, 0);
    	fmt.Println(newArrayList.ToString())
    	newArrayList.Insert(41, 41);
    	fmt.Println(newArrayList.ToString())
    	newArrayList.Insert(1, 111);
    	fmt.Println(newArrayList.ToString())
    	it := newArrayList.Iterator()
    	
    	for  it.HashNext() {
        
    		it.Next()
    		it.Remove()
    	}
    
    
    }

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