leetcode_01

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* twoSum(int* nums, int numsSize, int target, int* returnSize){

    // 表存資料數據的node
    struct data_node{
        struct data_node *next;	
        int value;		// value
        int index;      //index
    };

    // Hash 表結構體定義
    typedef struct Hash_Node{
        struct data_node *p;	
    }hash_node;

    hash_node* HashTable = (hash_node*)malloc(numsSize * sizeof(hash_node));//宣告一個hashtable
    if (HashTable == NULL){
        *returnSize = 0;
        return NULL;
    }  

    void InitHashTable(hash_node *HashTable){
        //參數初始化
        for(int i = 0; i < numsSize; i++){
            HashTable[i].p = NULL;
        }
    }

    int savedata(struct data_node **head, int num ,int i){
            struct data_node *temp_p = *head;
            struct data_node *s = (struct data_node *)malloc(sizeof(struct data_node));
            if(s == NULL){
                return -1;
            }
            s->index = i;
            s->value = num;
            s->next = NULL;

            if(*head == NULL){
                *head = s;
            }
            else{ //如果該hashtable格子不為空,則應該添加到link list尾端   
            
                while(temp_p != NULL){
                    if(temp_p->next == NULL)
                            break;
                    temp_p =temp_p->next;     
                }
                temp_p->next = s;
            }
        return 0;
    }

    int add_hash(hash_node *HashTable, int num, int i){
       
        int sum = num % numsSize;

        if(sum < 0){
            sum *= -1;
        }
        return savedata(&HashTable[sum].p, num, i);
    }


// hash table 製作完成

InitHashTable(HashTable);

int *result = (int*)malloc(2*sizeof(int));
if (result == NULL){
    *returnSize = 0;
    return NULL;
}

for(int i=0;i < numsSize; i++){//把資料添加到hash table
add_hash(HashTable, nums[i], i);
}

struct data_node* pointerToData;
int need = 0;

for(int i=0;i < numsSize; i++){
    need = (target - nums[i]) % numsSize;
    if(need < 0){
        need *= -1;
    }
    pointerToData = HashTable[need].p;

    while(pointerToData != NULL){
        if(nums[i] + pointerToData->value == target && i != pointerToData->index){
        result[1] = pointerToData->index;
        result[0] = i;
        *returnSize = 2;
        return result;
        }
        pointerToData = pointerToData->next;
    }

}
        *returnSize=0;
        return 0 ; 

}//int* twoSum