hash 散列算法-除留余数法实现

给定一个整数数组 nums 和一个整数目标值 target
在数组中找出和为目标值 target 的那两个整数, 并返回他们的数组下标

假设:

• 每种输入对应一个答案,
• 数组中同一个元素只能出现一次

/**
 * 需要使用 hash 散列算法实现
 * 散列函数: 除留余数法
 * 冲突解决: 链表存储
 */
struct HashNode
{
    unsigned char flag; // 0 未使用, 已使用 
    int key;
    long val;   //value -- index
    struct HashNode *next; 
};
/**
 * 插入 HashNode
 * @param node 节点数组 @param key  存储的 key @param val  存储的值  @param n 常量
 **/ 
void insert_HashNode(struct HashNode * node,  int key, long val, int n) {
    int index = abs(key) % n;
    struct HashNode * cnode = &node[index];
    if(cnode->flag == 0) {
        cnode->flag = 1;
        cnode->val = val;
        cnode->key = key;
        return;
    }
    while(cnode->next != NULL) {
        // cnode->next = cnode->next->next; 
        cnode = cnode->next;
    }
    cnode->next = (struct HashNode *) malloc(sizeof(struct HashNode));
    cnode->next->val = val;
    cnode->next->key = key;
}
/**
 * 查找 HashNode
 * @param node 节点数组 @param key  存储的 key  @param n 常量
 **/ 
int search_HashNode(struct HashNode * node, int key, int n){
    int index = abs(key) % n;
    struct HashNode * cnode = &node[index];
    if(cnode->flag == 0) return -1;
    do
    {
        if(cnode->key==key) {
            return cnode->val;
        }
        cnode = cnode->next;
    } while (NULL != cnode);
    return -1;
}
/**
 * 释放  HashNode 子节点 和 主节点
 */
void free_HashNode(struct HashNode * node, int n){
    while(n > 0) {
        struct HashNode * cnode = &node[--n];
        if(cnode->flag == 1) {
            cnode = cnode->next;
            while (NULL != cnode)
            {
                void *point = cnode->next;
                // printf("index: %d, node->key: %d, node->val: %d; node->next: %d ;\n",n, cnode->key, cnode->val, cnode->next);
                free(cnode);
                cnode = point;
            }
        }
    }
}

/***
 * 打印测试 HashNode
 * @param node HashNode @param n 常量 
 */ 
void print_HashNode(struct HashNode *node, int n) {
    for(int i = 0; i < n; i++) {
        struct HashNode *cnode = &node[i];
        printf("index: %d, node->key: %d, node->val: %d; node->next: %d ;\n",i, cnode->key, cnode->val, cnode->next);
        while(NULL != cnode->next) {
            cnode = cnode->next;
            printf("index: %d, node->key: %d, node->val: %d; node->next: %d ;\n",i, cnode->key, cnode->val, cnode->next);
        }
    }
}

uint8 solution(int *indexs, int size, int * nums, int target) {
    if(size < 2) return -1;
    struct HashNode *node = (struct HashNode *)malloc(size * sizeof(struct HashNode));
    //申请 大小为 size 的 node 数组
    for(int i = 0; i < size; i++) {
        int pindex = search_HashNode(node, target - nums[i], size);
        if(-1 == pindex){
            insert_HashNode(node, nums[i], i, size);
            continue;
        }
        indexs[0] = pindex;
        indexs[1] = i;
        free_HashNode(node, size);
        free(node);
        return 1;
    }
    free_HashNode(node, size);
    free(node);
    return 0;
}

void test() {
    int nums[] = { 2, 4, 1, 6, 8, 3, 9, 3 };
    int target = 10;
    int indexs[2] = { 0 };
    if(solution(indexs, sizeof(nums)/sizeof(int), nums, target) == 1) {
        printf("res:[%d, %d] \n", indexs[0], indexs[1]);
    }else {
        printf("no res \n");
    }
}

void main() {
    test();
}
//测试输出结果 res:[1, 3]