链表的多重数组表示（算法导论10-3）

2024年6月8日 76次阅读

算法导论10-3中的结构。

//LinkByArray.h
#ifndef LINKBYARRAY_H_INCLUDED
#define LINKBYARRAY_H_INCLUDED
class LinkByMulArray{
    private:
        int size;//已有的元素个数
        int increase;//存储空间不够时增加的空间个数
        int length;//空间个数
        int* prev;//存储prev
        int* key;//存储值
        int* next;//存储next
        int head;//表头
        int free;//空闲链表的表头
        int allocate();//分配一个空间
        void Free(int);//释放一个空间
        void inflate();//增加存储空间
    public:
        LinkByMulArray();
        int search(int);//查找元素，找不到时返回-1，找到了就返回下标
        void Delete(int);//删除一个元素
        void insert(int);//插入一个元素
        void print();//打印链表中的值
};
#endif // LINKBYARRAY_H_INCLUDED
//LinkByArray.cpp
#include "LinkByArray.h"
#include <iostream>
#include <cstring>
using namespace std;
LinkByMulArray::LinkByMulArray():size(0),length(20),increase(10),head(-1),free(0){
    prev = new int[length];
    key = new int[length];
    next = new int[length];
    memset(key,-1,sizeof(int)*length);//数组key全部设为-1
    for(int i = 0; i < length;i++){//初始化prev和next
        if(i == length - 1){
            next[i] = -1;
            prev[i] = i - 1;
        }else if(i == 0){
            prev[i] = -1;
            next[i] = i + 1;
        }else{
            next[i] = i+1;
            prev[i] = i-1;
        }
    }
}

void LinkByMulArray::inflate(){
    int newLength = length + increase;
    int* newPrev = new int[newLength];
    int* newKey = new int[newLength];
    int* newNext = new int[newLength];
    memcpy(newPrev,prev,sizeof(int)*length);//把原数组的数值全部复制到新数组中
    memcpy(newKey,key,sizeof(int)*length);
    memcpy(newNext,next,sizeof(int)*length);
    for(int i = length; i < newLength; i++){//初始化新空间里的prev和next
         if(i == newLength - 1){
            newNext[i] = -1;
            newPrev[i] = i - 1;
        }else{
            newNext[i] = i+1;
            newPrev[i] = i-1;
        }
    }
    free = length;//free指向新分配的空间
    length = newLength;
    delete[] prev;//释放原数组
    delete[] key;
    delete[] next;
    prev = newPrev;
    key = newKey;
    next = newNext;
}

int LinkByMulArray::allocate(){
    if(free == -1){
        inflate();
    }
    int temp = free;
    free = next[free];
    return temp;
}

void LinkByMulArray::Free(int i){
    next[i] = free;
    free = i;
}

void LinkByMulArray::insert(int i){//表头插入
    int index = allocate();
    key[index] = i;
    next[index] = head;
    prev[next[index]] = index;
    prev[index] = -1;
    head = index;
    size++;
}

int LinkByMulArray::search(int k){
    int i;
    for(i = head; (i != -1)&&(key[i] != k);i = next[i]);
    return i;
}

void LinkByMulArray::Delete(int i){
    int temp = search(i);
    if(temp != -1){
        prev[next[temp]] = prev[temp];
        next[prev[temp]] = next[temp];
        Free(temp);
        if(temp == head){
            head = next[temp];
        }
    }
    size--;
}

void LinkByMulArray::print(){
    for(int i = head, j = 0; (i != -1)&&(j < size); i = next[i],j++){
        cout << key[i] << endl;
    }
}
//main.cpp
#include <iostream>
#include "LinkByArray.h"
using namespace std;

int main()
{
    LinkByMulArray l;
    for(int i = 0; i < 30; i++){
        l.insert(i);
    }
    l.Delete(23);
    l.print();

    return 0;
}
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