pub fn encode(value: isize) usize {
    if (value < 0) return @as(usize, @intCast(value * -1)) * 2 - 1;
    return @as(usize, @intCast(value)) * 2;
}

pub fn decode(value: usize) isize {
    if (value & 1 == 1) return -@as(isize, @intCast(value / 2)) - 1;
    return @as(isize, @intCast(value / 2));
}

test "zigzag.encode val = 10" {
    const testing = @import("std").testing;

    const encoded = encode(10);
    try testing.expectEqual(20, encoded);
}

test "zigzag.encode val = -42" {
    const testing = @import("std").testing;

    const encoded = encode(-42);
    try testing.expectEqual(83, encoded);
}

test "zigzag.decode val = 20" {
    const testing = @import("std").testing;

    const decoded = decode(20);
    try testing.expectEqual(10, decoded);
}

test "zigzag.decode val = 83" {
    const testing = @import("std").testing;

    const decoded = decode(83);
    try testing.expectEqual(-42, decoded);
}