The code is below:
WHY WA :-(

#include <stdio.h>

struct point
{
    long x;
    long y;
    int id;
};


void Sort (point points[], int n)
{
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n - i - 1; j++)
        {
            double r1 = points[j+1].y * points[j].x;
            double r2 = points[j].y * points[j+1].x;
            if (r1 < r2)
            {
                point t = points[j];
                points[j] = points[j+1];
                points[j+1] = t;
            }
        }
    }
}

void main()
{
    int N = 0;
    scanf ("%d", &N);

    const int MAX = 10000;
    point points[MAX] = {0};

    for (int i = 0; i < N; i++)
    {
        scanf ("%ld%ld", &points[i].x, &points[i].y);
        points[i].id = i + 1;
    }

    Sort (points, N);

    printf ("%d %d", points[0].id, points[N/2].id);

}