pdq.zig

pdq.zig

pub fn pdq(
    comptime T: type,
    items: []T,
    context: anytype,
    comptime lessThanFn: fn (context: @TypeOf(context), lhs: T, rhs: T) bool,
) void {
    const Context = struct {
        items: []T,
        sub_ctx: @TypeOf(context),

        pub fn lessThan(ctx: @This(), a: usize, b: usize) bool {
            return lessThanFn(ctx.sub_ctx, ctx.items[a], ctx.items[b]);
        }

        pub fn swap(ctx: @This(), a: usize, b: usize) void {
            return mem.swap(T, &ctx.items[a], &ctx.items[b]);
        }
    };
    pdqContext(0, items.len, Context{ .items = items, .sub_ctx = context });
}

const Hint = enum {
    increasing,
    decreasing,
    unknown,
};