Nixyri/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2025-02-13 16:10:19 +00:00
Code Issues Packages Projects Releases Wiki Activity

implement insertion sort. something's broken

Browse Source
This commit is contained in:
Josh Wolfe 2017-12-01 16:11:39 -07:00
parent 921825b4c0
commit 67b8b00c44
1 changed files with 69 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
std/sort.zig
View File

@ -4,6 +4,19 @@ const math = @import("math/index.zig");
pub const Cmp = math.Cmp;
/// Stable sort using O(1) space. Currently implemented as insertion sort.
pub fn sort_stable(comptime T: type, array: []T, comptime cmp: fn(a: &const T, b: &const T)->Cmp) {
{var i: usize = 1; while (i < array.len) : (i += 1) {
const x = array[i];
var j: usize = i;
while (j > 0 and cmp(array[j - 1], x) == Cmp.Greater) : (j -= 1) {
array[j] = array[j - 1];
}
array[j] = x;
}}
}
/// Unstable sort using O(n) stack space. Currentl implemented as quicksort.
pub fn sort(comptime T: type, array: []T, comptime cmp: fn(a: &const T, b: &const T)->Cmp) {
if (array.len > 0) {
quicksort(T, array, 0, array.len - 1, cmp);
@ -58,6 +71,62 @@ fn reverse(was: Cmp) -> Cmp {
// ---------------------------------------
// tests
test "stable sort" {
testStableSort();
comptime testStableSort();
}
fn testStableSort() {
var 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| {
sort_stable(IdAndValue, (*case)[0..], cmpByValue);
for (*case) |item, i| {
assert(item.id == expected[i].id);
assert(item.value == expected[i].value);
}
}
}
const IdAndValue = struct {
id: i32,
value: i32,
};
fn cmpByValue(a: &const IdAndValue, b: &const IdAndValue) -> Cmp {
return i32asc(a.value, b.value);
}
test "testSort" {
const u8cases = [][]const []const u8 {
[][]const u8{"", ""},