# Two Sum Emma Note
## Programming Language: C
### Back to [Leetcode Blind 75 Practice Note](/xh5b5HXPTHGz_jwwymNKlw)
[Leetcode: Two Sum](https://leetcode.com/problems/two-sum/)

* 一開始我寫的有錯誤：

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* twoSum(int* nums, int numsSize, int target, int* returnSize)
{
    returnSize = malloc(2*sizeof(int));

    for (int i = 0; i < numsSize; i++)
    {
        for (int j = 1; j < numsSize; j++)
        {
            if ( (nums[i] + nums[j]) == target )
            {
                returnSize[0] = i;
                returnSize[1] = j;
                return returnSize;
            }
        }
    }
    return NULL;
}

* 錯誤如下
* Case 1
* Case 2
* Case 3

* 錯誤原因：
1. 搞錯returnSize的意思
* returnSize 的意思是要return多少個int，不是return那個array
* 所以要自訂新的array傳回去

    int* returnArray = malloc(2*sizeof(int)); // New array to pass out
    *returnSize = 2; // Return 2 integers

* 正確答案

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* twoSum(int* nums, int numsSize, int target, int* returnSize)
{
    int* returnArray = malloc(2*sizeof(int));
    *returnSize = 2;

    for (int i = 0; i < numsSize; i++)
    {
        for (int j = i+1; j < numsSize; j++)
        {
            if ( ((nums[i] + nums[j]) == target) && i != j )
            {
                returnArray[0] = i;
                returnArray[1] = j;

                return returnArray;
            }
        }
    }
    return -1;
}