[350] Intersection of Two Arrays II

嗯？！ 明明上周才寫過前身，但已經失憶 TOT

/**

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

*/

int* intersect(int* nums1, int nums1Size, int* nums2, int nums2Size, int* returnSize) {

int *hash = calloc (1001, sizeof(int));

for (int i=0; i<nums1Size; i++)

hash[nums1[i]]++;

int *ret = calloc (nums1Size, sizeof(int));

int idx = 0;

for (int i=0; i<nums2Size; i++)

{

if (hash[nums2[i]]>0)

{

hash[nums2[i]]--;

ret[idx++]= nums2[i];

}

}

*returnSize = idx;

return ret;

}