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Update examples for Zig (#287)

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* update zig in chapters 1-6

* fix zig dijkstras algo

* fix zig greedy algo

* fix longest_common_subsequence in zig

* cleanup

* test: use testing allocator
This commit is contained in:
Paolo Grisoli
2024-12-07 14:29:48 +01:00
committed by GitHub
parent 177581a9a4
commit 8a13efde83
13 changed files with 357 additions and 260 deletions
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4
04_quicksort/zig/01_loop_sum.zig
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@@ -17,7 +17,7 @@ fn sum(comptime T: type, arr: []T) T {
test "sum" {
var arr0 = [_]i32{ 1, 2, 3, 4 };
var arr1 = [_]i32{};
var tests = [_]struct {
const tests = [_]struct {
arr: []i32,
exp: i32,
}{
@@ -32,7 +32,7 @@ test "sum" {
};
for (tests) |t| {
var n = sum(@TypeOf(t.exp), t.arr);
const n = sum(@TypeOf(t.exp), t.arr);
try expect(n == t.exp);
}
}

4
04_quicksort/zig/02_recursive_sum.zig
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@@ -16,7 +16,7 @@ fn sum(comptime T: type, list: []T) T {
test "sum" {
var arr0 = [_]i32{ 1, 2, 3, 4 };
var arr1 = [_]i32{};
var tests = [_]struct {
const tests = [_]struct {
arr: []i32,
exp: i32,
}{
@@ -31,7 +31,7 @@ test "sum" {
};
for (tests) |t| {
var n = sum(@TypeOf(t.exp), t.arr);
const n = sum(@TypeOf(t.exp), t.arr);
try expect(n == t.exp);
}
}

2
04_quicksort/zig/03_recursive_count.zig
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@@ -16,7 +16,7 @@ test "count" {
var arr0 = [_]i32{};
var arr1 = [_]i32{42};
var arr2 = [_]i32{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
var tests = [_]struct {
const tests = [_]struct {
arr: []i32,
exp: i32,
}{

17
04_quicksort/zig/05_quicksort.zig
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@@ -32,8 +32,8 @@ fn quicksort(comptime T: type, allocator: mem.Allocator, s: []const T) anyerror!
}
}
var low = try quicksort(T, allocator, lower.items);
var high = try quicksort(T, allocator, higher.items);
const low = try quicksort(T, allocator, lower.items);
const high = try quicksort(T, allocator, higher.items);
var res = std.ArrayList(T).init(allocator);
try res.appendSlice(low);
@@ -44,13 +44,8 @@ fn quicksort(comptime T: type, allocator: mem.Allocator, s: []const T) anyerror!
}
test "quicksort" {
var gpa = heap.GeneralPurposeAllocator(.{}){};
var arena = heap.ArenaAllocator.init(gpa.allocator());
defer {
arena.deinit();
const leaked = gpa.deinit();
if (leaked) std.testing.expect(false) catch @panic("TEST FAIL"); //fail test; can't try in defer as defer is executed after we return
}
var arena = heap.ArenaAllocator.init(std.testing.allocator);
defer arena.deinit();
const tests = [_]struct {
s: []const u8,
@@ -71,9 +66,9 @@ test "quicksort" {
};
for (tests) |t| {
var res = try quicksort(u8, arena.allocator(), t.s);
const res = try quicksort(u8, arena.allocator(), t.s);
try expect(res.len == t.exp.len);
for (res) |e, i|
for (res, 0..) |e, i|
try expect(e == t.exp[i]);
}
}

82
04_quicksort/zig/06_quicksort_parallel.zig
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@@ -4,32 +4,31 @@ const expect = std.testing.expect;
const heap = std.heap;
const mem = std.mem;
pub const io_mode = .evented;
pub const Error = error{OutOfMemory};
// pub const io_mode = .evented;
pub fn main() !void {
var gpa = heap.GeneralPurposeAllocator(.{}){};
var arena = heap.ArenaAllocator.init(gpa.allocator());
defer arena.deinit();
var s = [_]u8{ 5, 3, 6, 2, 10 };
var u = [_]u8{ 5, 3, 6, 2, 10 };
print("{d}\n", .{try quicksort(arena.allocator(), &s)});
var s = try std.ArrayList(u8).initCapacity(arena.allocator(), u.len);
try quicksort(u8, arena.allocator(), &u, &s);
print("{d}\n", .{s.items});
}
// NOTE: this async version cannot be generic because allocating a frame for a
// generic function is not trivial.
fn quicksort(allocator: mem.Allocator, s: []const u8) Error![]const u8 {
if (s.len < 2) {
return s;
fn quicksort(comptime T: type, allocator: mem.Allocator, u: []const T, s: *std.ArrayList(T)) !void {
if (u.len < 2) {
try s.appendSlice(u);
return;
}
var lower = std.ArrayList(u8).init(allocator);
var higher = std.ArrayList(u8).init(allocator);
var lower = std.ArrayList(T).init(allocator);
var higher = std.ArrayList(T).init(allocator);
const pivot = s[0];
for (s[1..]) |item| {
const pivot = u[0];
for (u[1..]) |item| {
if (item <= pivot) {
try lower.append(item);
} else {
@@ -37,27 +36,41 @@ fn quicksort(allocator: mem.Allocator, s: []const u8) Error![]const u8 {
}
}
const low_frame = try allocator.create(@Frame(quicksort));
low_frame.* = async quicksort(allocator, lower.items);
var high = try quicksort(allocator, higher.items);
var low = try await low_frame;
// NOTE: zig has temporary removed the async/await syntax since v0.11.0
//
// const low_frame = try allocator.create(@Frame(quicksort));
// low_frame.* = async quicksort(allocator, lower.items);
// const high = try quicksort(allocator, higher.items);
// const low = try await low_frame;
var res = std.ArrayList(u8).init(allocator);
try res.appendSlice(low);
try res.append(pivot);
try res.appendSlice(high);
var low = try std.ArrayList(T).initCapacity(allocator, lower.items.len);
var high = try std.ArrayList(T).initCapacity(allocator, higher.items.len);
return res.items;
var low_handle = try std.Thread.spawn(
.{},
quicksort,
.{ T, allocator, lower.items, &low },
);
var high_handle = try std.Thread.spawn(
.{},
quicksort,
.{ T, allocator, higher.items, &high },
);
low_handle.join();
high_handle.join();
const lows = try low.toOwnedSlice();
const highs = try high.toOwnedSlice();
try s.appendSlice(lows);
try s.append(pivot);
try s.appendSlice(highs);
return;
}
test "quicksort" {
var gpa = heap.GeneralPurposeAllocator(.{}){};
var arena = heap.ArenaAllocator.init(gpa.allocator());
defer {
arena.deinit();
const leaked = gpa.deinit();
if (leaked) std.testing.expect(false) catch @panic("TEST FAIL"); //fail test; can't try in defer as defer is executed after we return
}
var arena = heap.ArenaAllocator.init(std.testing.allocator);
defer arena.deinit();
const tests = [_]struct {
s: []const u8,
@@ -78,9 +91,10 @@ test "quicksort" {
};
for (tests) |t| {
var res = try quicksort(arena.allocator(), t.s);
try expect(res.len == t.exp.len);
for (res) |e, i|
try expect(e == t.exp[i]);
var res = std.ArrayList(u8).init(arena.allocator());
try quicksort(u8, arena.allocator(), t.s, &res);
try expect(res.items.len == t.exp.len); // length not matching
for (res.items, 0..) |e, i|
try expect(e == t.exp[i]); // element not matching
}
}