algorithm fun

[mzimmers]

Hi all -

Imagine an array of n items. Given an index v, your task is to "normalize" v so that 0 <= v < n. Two catches:

1. When the indices extend beyond 0-9, they don't merely repeat; they "mirror." So, if n = 3,

v  v'
0 0
1 1
2 2
3 2
4 1
5 0

2. must work for negative values of v.

This didn't seem that complicated at first glance, but I had a heck of a time with it. My solution works, but I'm wondering whether any of you math wizards can simplify it. Here's my solution:

int getReal(int v, int n) {
    int x;
    int y;
    int z;

    x = abs(v);

    y = x % (2*n);

    if (y >= n) {
        z = n - (x % n) - 1;
    } else {
        z = x % n;
    }

    printf("%3d %3d\n", v, z);

    return z;
}

Thanks...