第十五周项目1-(1)-验证哈希表实施查找的相关算法
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问题及代码:
哈希表及算法的实现代码:- #include <stdio.h>
- #define MaxSize 100 //定义最大哈希表长度
- #define NULLKEY -1 //定义空关键字值
- #define DELKEY -2 //定义被删关键字值
- typedef int KeyType;
- typedef char * InfoType;
- typedef struct
- {
- KeyType key;
- InfoType data;
- int count;
- } HashData;
-
- typedef HashData HashTable[MaxSize];
-
- void InsertHT(HashTable ha,int &n,KeyType k,int p)
- {
- int i,adr;
- adr=k % p;
- if (ha[adr].key==NULLKEY || ha[adr].key==DELKEY)
- {
- ha[adr].key=k;
- ha[adr].count=1;
- }
- else
- {
- i=1;
- do
- {
- adr=(adr+1) % p;
- i++;
- }
- while (ha[adr].key!=NULLKEY && ha[adr].key!=DELKEY);
- ha[adr].key=k;
- ha[adr].count=i;
- }
- n++;
- }
- void CreateHT(HashTable ha,KeyType x[],int n,int m,int p)
- {
- int i,n1=0;
- for (i=0; i<m; i++)
- {
- ha[i].key=NULLKEY;
- ha[i].count=0;
- }
- for (i=0; i<n; i++)
- InsertHT(ha,n1,x[i],p);
- }
- int SearchHT(HashTable ha,int p,KeyType k)
- {
- int i=0,adr;
- adr=k % p;
- while (ha[adr].key!=NULLKEY && ha[adr].key!=k)
- {
- i++;
- adr=(adr+1) % p;
- }
- if (ha[adr].key==k)
- return adr;
- else
- return -1;
- }
- int DeleteHT(HashTable ha,int p,int k,int &n)
- {
- int adr;
- adr=SearchHT(ha,p,k);
- if (adr!=-1)
- {
- ha[adr].key=DELKEY;
- n--;
- return 1;
- }
- else
- return 0;
- }
- void DispHT(HashTable ha,int n,int m)
- {
- float avg=0;
- int i;
- printf(" 哈希表地址:\t");
- for (i=0; i<m; i++)
- printf(" %3d",i);
- printf(" \n");
- printf(" 哈希表关键字:\t");
- for (i=0; i<m; i++)
- if (ha[i].key==NULLKEY || ha[i].key==DELKEY)
- printf(" ");
- else
- printf(" %3d",ha[i].key);
- printf(" \n");
- printf(" 搜索次数:\t");
- for (i=0; i<m; i++)
- if (ha[i].key==NULLKEY || ha[i].key==DELKEY)
- printf(" ");
- else
- printf(" %3d",ha[i].count);
- printf(" \n");
- for (i=0; i<m; i++)
- if (ha[i].key!=NULLKEY && ha[i].key!=DELKEY)
- avg=avg+ha[i].count;
- avg=avg/n;
- printf(" 平均搜索长度ASL(%d)=%g\n",n,avg);
- }
- int main()
- {
- int x[]= {16,74,60,43,54,90,46,31,29,88,77};
- int n=11,m=13,p=13,i,k=29;
- HashTable ha;
- CreateHT(ha,x,n,m,p);
- printf("\n");
- DispHT(ha,n,m);
- i=SearchHT(ha,p,k);
- if (i!=-1)
- printf(" ha[%d].key=%d\n",i,k);
- else
- printf(" 未找到%d\n",k);
- k=77;
- printf(" 删除关键字%d\n",k);
- DeleteHT(ha,p,k,n);
- DispHT(ha,n,m);
- i=SearchHT(ha,p,k);
- if (i!=-1)
- printf(" ha[%d].key=%d\n",i,k);
- else
- printf(" 未找到%d\n",k);
- printf(" 插入关键字%d\n",k);
- InsertHT(ha,n,k,p);
- DispHT(ha,n,m);
- printf("\n");
- return 0;
- }
运行结果:
知识点总结:
为了更方便的查找,可以用要查找的关键字为自变量,带入到哈希表中查找地址。
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