1>请编程实现哈希表的创建存储数组{12,24,234,234,23,234,23}，输入key查找的值，实现查找功能。
代码：
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
typedef int datatype;
typedef struct Node{datatype data;struct Node *next;
}*node;int maxprime(int m);
node create();
void insert_hash(int key,int p,node hash[]);
void output(node hash[],int m);
void search_hash(datatype key,int p,node hash[]);int main(int argc,const char *argv[]){int arr[]={12,24,234,234,23,234,23};int len=sizeof(arr)/sizeof(arr[0]);int m=len*4/3;int p=maxprime(m);node hash[m];for(int i=0;i<m;i++)hash[i]=NULL;for(int i=0;i<len;i++){insert_hash(arr[i],p,hash);output(hash,m);}
// search_hash(23,p,hash);return 0;
}int maxprime(int m){for(int i=m;i>=2;i--){int flag=0;for(int j=2;j<sqrt(i);j++){if(i%j==0)flag=1;break;}if(flag==0)return i;}
}
node create(){node p=(node)malloc(sizeof(struct Node));if(!p)return NULL;p->data=0;p->next=NULL;return p;
}
void insert_hash(int key,int p,node hash[]){int index=key%p;node q=create();q->data=key;if(!hash[index]){hash[index]=q;}else{q->next=hash[index];hash[index]=q;}
}void output(node hash[],int m){for(int i=0;i<m;i++){node p=hash[i];printf("hash[%d]:",i);while(p){printf("%d\t",p->data);p=p->next;}puts("");}puts("------------------------------");
}
void search_hash(datatype key,int p,node hash[]){int index=key%p;node q=hash[index];int flag=0;while(q){if(q->data==key){printf("can find %d\n",key);flag=1;break; }q=q->next;}if(flag==0)printf("No\n");
}结果：
2>现有数组{12,23,45,56,445,5676,6888}，请输入key实现二分查找。
代码：
#include<stdio.h>
#include<stdlib.h>
#include<string.h>int search(int arr[],int key,int low,int high){while(low<=high){int mid=(low+high)/2;if(arr[mid]==key)return mid;if(arr[mid]>key)return search(arr,key,low,mid-1);if(arr[mid]<key)return search(arr,key,mid+1,high);}return -1000000;
}
int main(int argc,const char *argv[]){int arr[]={12,23,45,56,445,5676,6888};int len=sizeof(arr)/sizeof(arr[0]);int key;printf("请输入关键字：");scanf("%d",&key);printf("%d\n",search(arr,key,0,len-1));return 0;
}结果：
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