Missing integer variation - O(n) solution needed [closed]

Answer 1

1. Create a binary array bin of N+1 length (C uses 0 based indexing)

2. Traverse the binary array O(n)

3. If A[i] is within the bounds of bin then mark bin entry at index A[i] as present or true.
4. Traverse the binary array again
5. Index of any bin entry that is not present or false is your missing integer

~

#include
#include
#include

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i;
    bool *bin = (bool *)calloc((N+1),sizeof(bool));

    for (i = 0; i < N; i++)
    {
        if (A[i] > 0 && A[i] < N+1)
        {
            bin[A[i]] = true;
        }
    }

    for (i = 1; i < N+1; i++)
    {
        if (bin[i] == false)
        {
            break;
        }
    }

    return i;
}