哈希查找

哈希查找（散列表查找）

步骤：1.确定散列函数及解决冲突的方法

           2.根据散列函数建造哈希表

           3.进行哈希查找

解决冲突方法：1.开放地址->（1.线性探测 2.线性补偿探测 3.随机探测 4.线性再散列）

                         2.链表法

---C语言实现

---本次实现散列函数采用除整取余法

---本次实现解决冲突采用链表法

---实现了哈希表的创建 查找

#include <stdio.h>#include <stdlib.h>#include <windows.h>typedef struct hashsraechnode{int value;struct hashsraechnode*pNext;}HashSraechNode;//哈希查找（散列表查找）//散列函数：除整取余 //解决地址冲突：链表法void HashSearch(int arr[],int length,int SearchNum){int StandardNum;//用数组长度当作标准建造散列函数HashSraechNode **Head = NULL;HashSraechNode *Temp = NULL;HashSraechNode *Del = NULL;int count;int IsSearchSucceed;//0:fail 1:successif(arr == NULL || length <= 0)return ;IsSearchSucceed = 0; StandardNum = length;//建造哈希表Head = (HashSraechNode **)malloc(sizeof(HashSraechNode *)*StandardNum);memset(Head,0,sizeof(HashSraechNode*)*StandardNum);for(count = 0;count<length;count++){Temp =  (HashSraechNode *)malloc(sizeof(HashSraechNode ));Temp->value = arr[count];Temp->pNext = NULL;if( !Head[ arr[count]%StandardNum ] ){//头添加避免遍历链表Temp->pNext = Head[ arr[count]%StandardNum ];Head[ arr[count]%StandardNum ] = Temp;}else{Head[ arr[count]%StandardNum ] = Temp;}}//哈希查找if( Head[ SearchNum%StandardNum ] ){Temp = Head[ SearchNum%StandardNum ];while(Temp){if(Temp->value == SearchNum){IsSearchSucceed = 1;break;}Temp = Temp->pNext;}}//释放空间for(count = 0;count<length;count++){if(Head[count]){Temp = Del = Head[count];while(Temp){Del = Temp;Temp = Temp->pNext;free(Del);Del = NULL;}}}free(Head);Head = NULL;if(IsSearchSucceed)printf("Search Succeed\n");elseprintf("Search Failed\n");return ;}int main(){int arr[] = {2,6,9,12,23,55,67,99,123};HashSearch(arr,sizeof(arr)/sizeof(arr[0]),6);system("pause");return 0;}