My code is here:
--------------
#include <iostream>
using namespace std;

int compare(const void * x1, const void * x2) {
    return (*(int*)x1 - *(int*)x2);
}

int main() {
    long N;
    cin >> N;
    int *m = new int [N];

    for (int i = 0; i < N; ++i) {
        cin >> m[i];
    }
    qsort(m, N, sizeof(int), compare);

    if (N % 2 == 0) {
        cout << (((m[(N - 1)/ 2] + m[N / 2]) / 2.0)*10)/10;
    }
    else {
        cout << m[N/2];
    }

    return 0;
}
--------------
Tell me please where I made a mistake

Try the following test:

4
2147483647
2147483647
2147483647
2147483647

how to bypass this test?