[442] Find All Duplicates in an Array

第一版！！！

竟然忘了count++ 真是太蠢了= = 

更新：後面看一看除了先sorting 以外好像也沒什麼特別的(thinking圖）

那就先這樣好了XD~~~

/**

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

*/

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

int* hash=calloc(100001,sizeof(int));

int count=0;

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

{

hash[nums[i]]++;

if (hash[nums[i]]==2)

count++;

}

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

*returnSize = count;

count=0;

for (int i=1;i<100001;i++)

if (hash[i]>=2)

ret[count++]=i;

return ret;

}