const std = @import("std.zig");
const assert = std.debug.assert;
const testing = std.testing;
const mem = std.mem;
const math = std.math;
pub const block = @import("sort/block.zig").block;
pub const pdq = @import("sort/pdq.zig").pdq;
pub const pdqContext = @import("sort/pdq.zig").pdqContext;
pub fn insertion(
comptime T: type,
items: []T,
context: anytype,
comptime lessThanFn: fn (@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]);
}
};
insertionContext(0, items.len, Context{ .items = items, .sub_ctx = context });
}
pub fn insertionContext(a: usize, b: usize, context: anytype) void {
var i = a + 1;
while (i < b) : (i += 1) {
var j = i;
while (j > a and context.lessThan(j, j - 1)) : (j -= 1) {
context.swap(j, j - 1);
}
}
}
pub fn heap(
comptime T: type,
items: []T,
context: anytype,
comptime lessThanFn: fn (@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]);
}
};
heapContext(0, items.len, Context{ .items = items, .sub_ctx = context });
}
pub fn heapContext(a: usize, b: usize, context: anytype) void {
var i = b / 2;
while (i > a) : (i -= 1) {
siftDown(i - 1, b, context);
}
i = b;
while (i > a) : (i -= 1) {
context.swap(a, i - 1);
siftDown(a, i - 1, context);
}
}
fn siftDown(root: usize, n: usize, context: anytype) void {
var node = root;
while (true) {
var child = 2 * node + 1;
if (child >= n) break;
if (child + 1 < n and context.lessThan(child, child + 1)) {
child += 1;
}
if (!context.lessThan(node, child)) break;
context.swap(node, child);
node = child;
}
}
pub fn asc(comptime T: type) fn (void, T, T) bool {
return struct {
pub fn inner(_: void, a: T, b: T) bool {
return a < b;
}
}.inner;
}
pub fn desc(comptime T: type) fn (void, T, T) bool {
return struct {
pub fn inner(_: void, a: T, b: T) bool {
return a > b;
}
}.inner;
}
const asc_u8 = asc(u8);
const asc_i32 = asc(i32);
const desc_u8 = desc(u8);
const desc_i32 = desc(i32);
const sort_funcs = &[_]fn (comptime type, anytype, anytype, comptime anytype) void{
block,
pdq,
insertion,
heap,
};
const IdAndValue = struct {
id: usize,
value: i32,
fn lessThan(context: void, a: IdAndValue, b: IdAndValue) bool {
_ = context;
return a.value < b.value;
}
};
test "stable sort" {
const expected = [_]IdAndValue{
IdAndValue{ .id = 0, .value = 0 },
IdAndValue{ .id = 1, .value = 0 },
IdAndValue{ .id = 2, .value = 0 },
IdAndValue{ .id = 0, .value = 1 },
IdAndValue{ .id = 1, .value = 1 },
IdAndValue{ .id = 2, .value = 1 },
IdAndValue{ .id = 0, .value = 2 },
IdAndValue{ .id = 1, .value = 2 },
IdAndValue{ .id = 2, .value = 2 },
};
var cases = [_][9]IdAndValue{
[_]IdAndValue{
IdAndValue{ .id = 0, .value = 0 },
IdAndValue{ .id = 0, .value = 1 },
IdAndValue{ .id = 0, .value = 2 },
IdAndValue{ .id = 1, .value = 0 },
IdAndValue{ .id = 1, .value = 1 },
IdAndValue{ .id = 1, .value = 2 },
IdAndValue{ .id = 2, .value = 0 },
IdAndValue{ .id = 2, .value = 1 },
IdAndValue{ .id = 2, .value = 2 },
},
[_]IdAndValue{
IdAndValue{ .id = 0, .value = 2 },
IdAndValue{ .id = 0, .value = 1 },
IdAndValue{ .id = 0, .value = 0 },
IdAndValue{ .id = 1, .value = 2 },
IdAndValue{ .id = 1, .value = 1 },
IdAndValue{ .id = 1, .value = 0 },
IdAndValue{ .id = 2, .value = 2 },
IdAndValue{ .id = 2, .value = 1 },
IdAndValue{ .id = 2, .value = 0 },
},
};
for (&cases) |*case| {
block(IdAndValue, (case.*)[0..], {}, IdAndValue.lessThan);
for (case.*, 0..) |item, i| {
try testing.expect(item.id == expected[i].id);
try testing.expect(item.value == expected[i].value);
}
}
}
test "sort" {
const u8cases = [_][]const []const u8{
&[_][]const u8{
"",
"",
},
&[_][]const u8{
"a",
"a",
},
&[_][]const u8{
"az",
"az",
},
&[_][]const u8{
"za",
"az",
},
&[_][]const u8{
"asdf",
"adfs",
},
&[_][]const u8{
"one",
"eno",
},
};
const i32cases = [_][]const []const i32{
&[_][]const i32{
&[_]i32{},
&[_]i32{},
},
&[_][]const i32{
&[_]i32{1},
&[_]i32{1},
},
&[_][]const i32{
&[_]i32{ 0, 1 },
&[_]i32{ 0, 1 },
},
&[_][]const i32{
&[_]i32{ 1, 0 },
&[_]i32{ 0, 1 },
},
&[_][]const i32{
&[_]i32{ 1, -1, 0 },
&[_]i32{ -1, 0, 1 },
},
&[_][]const i32{
&[_]i32{ 2, 1, 3 },
&[_]i32{ 1, 2, 3 },
},
};
inline for (sort_funcs) |sortFn| {
for (u8cases) |case| {
var buf: [8]u8 = undefined;
const slice = buf[0..case[0].len];
@memcpy(slice, case[0]);
sortFn(u8, slice, {}, asc_u8);
try testing.expect(mem.eql(u8, slice, case[1]));
}
for (i32cases) |case| {
var buf: [8]i32 = undefined;
const slice = buf[0..case[0].len];
@memcpy(slice, case[0]);
sortFn(i32, slice, {}, asc_i32);
try testing.expect(mem.eql(i32, slice, case[1]));
}
}
}
test "sort descending" {
const rev_cases = [_][]const []const i32{
&[_][]const i32{
&[_]i32{},
&[_]i32{},
},
&[_][]const i32{
&[_]i32{1},
&[_]i32{1},
},
&[_][]const i32{
&[_]i32{ 0, 1 },
&[_]i32{ 1, 0 },
},
&[_][]const i32{
&[_]i32{ 1, 0 },
&[_]i32{ 1, 0 },
},
&[_][]const i32{
&[_]i32{ 1, -1, 0 },
&[_]i32{ 1, 0, -1 },
},
&[_][]const i32{
&[_]i32{ 2, 1, 3 },
&[_]i32{ 3, 2, 1 },
},
};
inline for (sort_funcs) |sortFn| {
for (rev_cases) |case| {
var buf: [8]i32 = undefined;
const slice = buf[0..case[0].len];
@memcpy(slice, case[0]);
sortFn(i32, slice, {}, desc_i32);
try testing.expect(mem.eql(i32, slice, case[1]));
}
}
}
test "sort fuzz testing" {
var prng = std.rand.DefaultPrng.init(0x12345678);
const random = prng.random();
const test_case_count = 10;
inline for (sort_funcs) |sortFn| {
var i: usize = 0;
while (i < test_case_count) : (i += 1) {
const array_size = random.intRangeLessThan(usize, 0, 1000);
var array = try testing.allocator.alloc(i32, array_size);
defer testing.allocator.free(array);
for (array) |*item| {
item.* = random.intRangeLessThan(i32, 0, 100);
}
sortFn(i32, array, {}, asc_i32);
try testing.expect(isSorted(i32, array, {}, asc_i32));
}
}
}
pub fn binarySearch(
comptime T: type,
key: anytype,
items: []const T,
context: anytype,
comptime compareFn: fn (context: @TypeOf(context), key: @TypeOf(key), mid_item: T) math.Order,
) ?usize {
var left: usize = 0;
var right: usize = items.len;
while (left < right) {
const mid = left + (right - left) / 2;
switch (compareFn(context, key, items[mid])) {
.eq => return mid,
.gt => left = mid + 1,
.lt => right = mid,
}
}
return null;
}
test "binarySearch" {
const S = struct {
fn order_u32(context: void, lhs: u32, rhs: u32) math.Order {
_ = context;
return math.order(lhs, rhs);
}
fn order_i32(context: void, lhs: i32, rhs: i32) math.Order {
_ = context;
return math.order(lhs, rhs);
}
};
try testing.expectEqual(
@as(?usize, null),
binarySearch(u32, @as(u32, 1), &[_]u32{}, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, 0),
binarySearch(u32, @as(u32, 1), &[_]u32{1}, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, null),
binarySearch(u32, @as(u32, 1), &[_]u32{0}, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, null),
binarySearch(u32, @as(u32, 0), &[_]u32{1}, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, 4),
binarySearch(u32, @as(u32, 5), &[_]u32{ 1, 2, 3, 4, 5 }, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, 0),
binarySearch(u32, @as(u32, 2), &[_]u32{ 2, 4, 8, 16, 32, 64 }, {}, S.order_u32),
);
try testing.expectEqual(
@as(?usize, 1),
binarySearch(i32, @as(i32, -4), &[_]i32{ -7, -4, 0, 9, 10 }, {}, S.order_i32),
);
try testing.expectEqual(
@as(?usize, 3),
binarySearch(i32, @as(i32, 98), &[_]i32{ -100, -25, 2, 98, 99, 100 }, {}, S.order_i32),
);
const R = struct {
b: i32,
e: i32,
fn r(b: i32, e: i32) @This() {
return @This(){ .b = b, .e = e };
}
fn order(context: void, key: i32, mid_item: @This()) math.Order {
_ = context;
if (key < mid_item.b) {
return .lt;
}
if (key > mid_item.e) {
return .gt;
}
return .eq;
}
};
try testing.expectEqual(
@as(?usize, null),
binarySearch(R, @as(i32, -45), &[_]R{ R.r(-100, -50), R.r(-40, -20), R.r(-10, 20), R.r(30, 40) }, {}, R.order),
);
try testing.expectEqual(
@as(?usize, 2),
binarySearch(R, @as(i32, 10), &[_]R{ R.r(-100, -50), R.r(-40, -20), R.r(-10, 20), R.r(30, 40) }, {}, R.order),
);
try testing.expectEqual(
@as(?usize, 1),
binarySearch(R, @as(i32, -20), &[_]R{ R.r(-100, -50), R.r(-40, -20), R.r(-10, 20), R.r(30, 40) }, {}, R.order),
);
}
pub fn argMin(
comptime T: type,
items: []const T,
context: anytype,
comptime lessThan: fn (@TypeOf(context), lhs: T, rhs: T) bool,
) ?usize {
if (items.len == 0) {
return null;
}
var smallest = items[0];
var smallest_index: usize = 0;
for (items[1..], 0..) |item, i| {
if (lessThan(context, item, smallest)) {
smallest = item;
smallest_index = i + 1;
}
}
return smallest_index;
}
test "argMin" {
try testing.expectEqual(@as(?usize, null), argMin(i32, &[_]i32{}, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMin(i32, &[_]i32{1}, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMin(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 3), argMin(i32, &[_]i32{ 9, 3, 8, 2, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMin(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMin(i32, &[_]i32{ -10, 1, 10 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 3), argMin(i32, &[_]i32{ 6, 3, 5, 7, 6 }, {}, desc_i32));
}
pub fn min(
comptime T: type,
items: []const T,
context: anytype,
comptime lessThan: fn (context: @TypeOf(context), lhs: T, rhs: T) bool,
) ?T {
const i = argMin(T, items, context, lessThan) orelse return null;
return items[i];
}
test "min" {
try testing.expectEqual(@as(?i32, null), min(i32, &[_]i32{}, {}, asc_i32));
try testing.expectEqual(@as(?i32, 1), min(i32, &[_]i32{1}, {}, asc_i32));
try testing.expectEqual(@as(?i32, 1), min(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 2), min(i32, &[_]i32{ 9, 3, 8, 2, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 1), min(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, -10), min(i32, &[_]i32{ -10, 1, 10 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 7), min(i32, &[_]i32{ 6, 3, 5, 7, 6 }, {}, desc_i32));
}
pub fn argMax(
comptime T: type,
items: []const T,
context: anytype,
comptime lessThan: fn (context: @TypeOf(context), lhs: T, rhs: T) bool,
) ?usize {
if (items.len == 0) {
return null;
}
var biggest = items[0];
var biggest_index: usize = 0;
for (items[1..], 0..) |item, i| {
if (lessThan(context, biggest, item)) {
biggest = item;
biggest_index = i + 1;
}
}
return biggest_index;
}
test "argMax" {
try testing.expectEqual(@as(?usize, null), argMax(i32, &[_]i32{}, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMax(i32, &[_]i32{1}, {}, asc_i32));
try testing.expectEqual(@as(?usize, 4), argMax(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMax(i32, &[_]i32{ 9, 3, 8, 2, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 0), argMax(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 2), argMax(i32, &[_]i32{ -10, 1, 10 }, {}, asc_i32));
try testing.expectEqual(@as(?usize, 1), argMax(i32, &[_]i32{ 6, 3, 5, 7, 6 }, {}, desc_i32));
}
pub fn max(
comptime T: type,
items: []const T,
context: anytype,
comptime lessThan: fn (context: @TypeOf(context), lhs: T, rhs: T) bool,
) ?T {
const i = argMax(T, items, context, lessThan) orelse return null;
return items[i];
}
test "max" {
try testing.expectEqual(@as(?i32, null), max(i32, &[_]i32{}, {}, asc_i32));
try testing.expectEqual(@as(?i32, 1), max(i32, &[_]i32{1}, {}, asc_i32));
try testing.expectEqual(@as(?i32, 5), max(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 9), max(i32, &[_]i32{ 9, 3, 8, 2, 5 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 1), max(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 10), max(i32, &[_]i32{ -10, 1, 10 }, {}, asc_i32));
try testing.expectEqual(@as(?i32, 3), max(i32, &[_]i32{ 6, 3, 5, 7, 6 }, {}, desc_i32));
}
pub fn isSorted(
comptime T: type,
items: []const T,
context: anytype,
comptime lessThan: fn (context: @TypeOf(context), lhs: T, rhs: T) bool,
) bool {
var i: usize = 1;
while (i < items.len) : (i += 1) {
if (lessThan(context, items[i], items[i - 1])) {
return false;
}
}
return true;
}
test "isSorted" {
try testing.expect(isSorted(i32, &[_]i32{}, {}, asc_i32));
try testing.expect(isSorted(i32, &[_]i32{10}, {}, asc_i32));
try testing.expect(isSorted(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, asc_i32));
try testing.expect(isSorted(i32, &[_]i32{ -10, 1, 1, 1, 10 }, {}, asc_i32));
try testing.expect(isSorted(i32, &[_]i32{}, {}, desc_i32));
try testing.expect(isSorted(i32, &[_]i32{-20}, {}, desc_i32));
try testing.expect(isSorted(i32, &[_]i32{ 3, 2, 1, 0, -1 }, {}, desc_i32));
try testing.expect(isSorted(i32, &[_]i32{ 10, -10 }, {}, desc_i32));
try testing.expect(isSorted(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, asc_i32));
try testing.expect(isSorted(i32, &[_]i32{ 1, 1, 1, 1, 1 }, {}, desc_i32));
try testing.expectEqual(false, isSorted(i32, &[_]i32{ 5, 4, 3, 2, 1 }, {}, asc_i32));
try testing.expectEqual(false, isSorted(i32, &[_]i32{ 1, 2, 3, 4, 5 }, {}, desc_i32));
try testing.expect(isSorted(u8, "abcd", {}, asc_u8));
try testing.expect(isSorted(u8, "zyxw", {}, desc_u8));
try testing.expectEqual(false, isSorted(u8, "abcd", {}, desc_u8));
try testing.expectEqual(false, isSorted(u8, "zyxw", {}, asc_u8));
try testing.expect(isSorted(u8, "ffff", {}, asc_u8));
try testing.expect(isSorted(u8, "ffff", {}, desc_u8));
}