20200202数据结构和算法之用哈希表实现DNA检测

可以使用哈希表来存储色盲基因库数据，通过哈希函数把 4 位色盲基因映射到哈希表中，大大提高检索的效率

#include<Windows.h>
#include<iostream>
#include<stdio.h>
using namespace std;
#define isEqual(a, b)  (0==strcmp((const char*)a,(const char*)b))

#define DEFAULT_SIZE 128

typedef struct _listNode {
	struct _listNode* next;
	void* key;
	void* data;
}listNode;

typedef listNode* list;
typedef listNode* element;

typedef struct _hashTable {
	int tableSize;
	list* theLists;
}hashTable;

hashTable* initHash(int tableSize);
int hashFunction(void* key, int tableSize);//哈希函数
element findElement(hashTable* &hashTable, void* key);
bool insertElement(hashTable* &hashTable, void* key, void* value);
bool deleteElement(hashTable* &hastTable, void* key);
unsigned int SDBMHash(void* key);
void destroyHash(hashTable* &hashTable);

int main() {
	const char* str[] = { "ABCD","BDCD","ACDB","BACD" };
	char tester[] = "ABDCDC";
	char tmp[5] = {0};
	strncpy_s(tmp,sizeof(tmp), tester + 1, 4);

	hashTable* hashTab = initHash(30);
	for (int i = 0; i < 4; i++) {
		if (insertElement(hashTab, (char*)str[i] , (char*)str[i])) {
			cout << "插入成功！" << endl;
		}
		else {
			cout << "插入失败！" << endl;
		}
	}

	if (!deleteElement(hashTab, (char*)str[3]))
		cout << "删除失败！" << endl;



	element E = findElement(hashTab, tmp);
	if (E) {
		cout << "找到的元素为:" << (char*)(E->data) << endl;
	}
	else
		cout << "未找到key对应的元素" << endl;

	destroyHash(hashTab);
	system("pause");
	return 0;
}
hashTable* initHash(int tableSize) {
	int i = 0;
	hashTable* hTable = NULL;
	if (tableSize <= 0) {
		tableSize = DEFAULT_SIZE;
	}
	hTable = (hashTable*)malloc(sizeof(hashTable));
	if (hTable == NULL) {
		cout << "hashTable malloc failure" << endl;
		return NULL;
	}
	hTable->tableSize = tableSize;

	//为哈希桶分配内存空间，其为一个指针数组
	hTable->theLists = (list*)malloc(tableSize * sizeof(list));
	if (hTable->theLists == NULL) {
		cout << "theLists malloc failure" << endl;
		free(hTable);
		return NULL;
	}

	//为哈希桶对应的指针数组初始化链表结点
	for (int i = 0; i < tableSize; i++) {
		hTable->theLists[i] = (listNode*)malloc(sizeof(listNode));
		if (hTable->theLists[i] == NULL) {
			cout << "theLists malloc failure" << endl;
			free(hTable->theLists);
			free(hTable);
			return NULL;
		}
		memset(hTable->theLists[i], 0, sizeof(listNode));
	}
	return hTable;
}
int hashFunction(void* key, int tableSize) {
	/*根据 key 计算索引，定位 Hash 桶的位置*/
	return (SDBMHash(key) % tableSize);
}
element findElement(hashTable* &hashTable, void* key) {
	int i = 0;
	list L = NULL;
	element E = NULL;
	i = hashFunction(key, hashTable->tableSize);
	L = hashTable->theLists[i];
	E = L->next;	
	while (E != NULL && !isEqual(E->key,key)) {
		E = E->next;
	}
	return E;
}
bool insertElement(hashTable* &hashTable, void* key, void* value) {
	element E = NULL, tmp = NULL;
	list L = NULL;
	E = findElement(hashTable, key);
	if (E == NULL) {
		tmp = (listNode*)malloc(sizeof(listNode));
		if (tmp == NULL) {
			printf("listNode malloc failure!");
			return false;
		}
		tmp->data = value;
		tmp->key = key;
		tmp->next = NULL;

		int index = hashFunction(key,hashTable->tableSize);
		L = hashTable->theLists[index];

		tmp->next = L->next;
		L->next = tmp;
		return true;
	}
	else {
		cout << "element already exits" << endl;
		return false;
	}

}
bool deleteElement(hashTable* &hashTable, void* key) {
	element E = NULL;
	element L = NULL;
	int index = hashFunction(key, hashTable->tableSize);
	L = hashTable->theLists[index];
	E = L->next;
	while ( E != NULL && !isEqual(E->key, key) ) {
		L = E;
		E = E->next;
	}
	if (E) {
		L->next = E->next;
		delete E;
		return true;
	}
	return 	false;
}
unsigned int SDBMHash(void* key) {
	unsigned int hash = 0;
	char* str = (char*)key;
	while (*str) {
		hash = (*str++) + (hash << 6) + (hash << 16) - hash;
	}
	return (hash & 0x7FFFFFFF);
}
void destroyHash(hashTable* &hashTable) {
	element E = NULL;
	element tmp = NULL;
	list L = NULL;

	for (int i = 0; i < hashTable->tableSize; i++) {
		L = hashTable->theLists[i];
		E = L->next;
		while (E) {
			tmp = E;
			E = E->next;
			delete tmp;
		}
		delete L;
	}
	delete hashTable->theLists;
	delete hashTable;
}