1. Two Sum - https://leetcode.com/problems/two-sum/
/**
* Note: The returned array must be malloced, assume caller calls free().
*/
int* twoSum(int* nums, int numsSize, int target, int* returnSize){
*returnSize = 2;
int *ret = malloc(sizeof(int) * *returnSize);
ret[0] = 0;
ret[1] = 1;
for (ret[0] = 0; ret[0] < numsSize - 1; ret[0]++) {
