[448] Find All Numbers Disappeared in an Array

找出array裡少掉的數字, 回傳它的index

一開始的想法好像會用掉很多memory

看完別人的解法就覺得自己是凡人, 哈哈哈

Find All Numbers Disappeared in an Array

/**

 * Return an array of size *returnSize.

 * Note: The returned array must be malloced, assume caller calls free().

 */

int* findDisappearedNumbers(int* nums, int numsSize, int* returnSize) {

    int* ret = malloc(sizeof(int)*(numsSize+1));

    int i;

    for (i=0;i<numsSize;i++)

    {

        ret[nums[i]] = 1;

    }

    

    for(i=1;i<=numsSize;i++)

    {

        //printf("%d: %d\n",i, ret[i]);

        if(ret[i]!=1)

        {

            ret[*returnSize] = i;

            *returnSize += 1;

        }

    }

    return ret;

}