I’m new to programming in C and wanted to try some LeetCode problems to get used to the language. Problem: I failed at the first task.
The task is to find matching pairs in an array which match up to the target parameter.

int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
    int length = sizeof(nums) / sizeof(nums[0]);
    int i, ii;
    int *Paar = (int*)malloc(2*sizeof(int));

    for(i=0; i<length; i++) {
        for(ii=0; ii<length; ii++) {
            if(i != ii) {
                if(nums[i] + nums[ii] == target) {
                    Paar[0] = i;
                    Paar[1] = ii;
                    *returnSize = 2;
                    return Paar;
                }
            }
        }
    }
    return Paar;
}

my approach was to just brute force the task.

Testcases:
For the input [2,7,11,15] and target 9 it works.
For the input [3,3] and target 6 it works.
For the input [3,2,4] and target 6 it does not work. There it uses the return at the end, which is just a placeholder.

I can imagine that the order of the elements could be the reason but I don’t know why this should be a problem since I’m checking every possibility.