authorgravatar for thejoshwolfe@gmail.comJosh Wolfe <thejoshwolfe@gmail.com> 2017-12-01 16:11:39-07:00
committergravatar for thejoshwolfe@gmail.comJosh Wolfe <thejoshwolfe@gmail.com> 2017-12-01 16:11:39-07:00
log67b8b00c446634a6db5818bcb84f4207aad3948a
treef9158a66d8f656f2e111ac151a77d0b95c4b23e0
parent921825b4c0a83c98782e1b9266522aefb1b17022

implement insertion sort. something's broken

1 files changed, 69 insertions(+), 0 deletions(-)

std/sort.zig+69
...@@ -4,6 +4,19 @@ const math = @import("math/index.zig");...@@ -4,6 +4,19 @@ const math = @import("math/index.zig");
44
5pub const Cmp = math.Cmp;5pub const Cmp = math.Cmp;
66
7/// Stable sort using O(1) space. Currently implemented as insertion sort.
8pub fn sort_stable(comptime T: type, array: []T, comptime cmp: fn(a: &const T, b: &const T)->Cmp) {
9 {var i: usize = 1; while (i < array.len) : (i += 1) {
10 const x = array[i];
11 var j: usize = i;
12 while (j > 0 and cmp(array[j - 1], x) == Cmp.Greater) : (j -= 1) {
13 array[j] = array[j - 1];
14 }
15 array[j] = x;
16 }}
17}
18
19/// Unstable sort using O(n) stack space. Currentl implemented as quicksort.
7pub fn sort(comptime T: type, array: []T, comptime cmp: fn(a: &const T, b: &const T)->Cmp) {20pub fn sort(comptime T: type, array: []T, comptime cmp: fn(a: &const T, b: &const T)->Cmp) {
8 if (array.len > 0) {21 if (array.len > 0) {
9 quicksort(T, array, 0, array.len - 1, cmp);22 quicksort(T, array, 0, array.len - 1, cmp);
...@@ -58,6 +71,62 @@ fn reverse(was: Cmp) -> Cmp {...@@ -58,6 +71,62 @@ fn reverse(was: Cmp) -> Cmp {
58// ---------------------------------------71// ---------------------------------------
59// tests72// tests
6073
74test "stable sort" {
75 testStableSort();
76 comptime testStableSort();
77}
78fn testStableSort() {
79 var expected = []IdAndValue {
80 IdAndValue{.id = 0, .value = 0},
81 IdAndValue{.id = 1, .value = 0},
82 IdAndValue{.id = 2, .value = 0},
83 IdAndValue{.id = 0, .value = 1},
84 IdAndValue{.id = 1, .value = 1},
85 IdAndValue{.id = 2, .value = 1},
86 IdAndValue{.id = 0, .value = 2},
87 IdAndValue{.id = 1, .value = 2},
88 IdAndValue{.id = 2, .value = 2},
89 };
90 var cases = [][9]IdAndValue {
91 []IdAndValue {
92 IdAndValue{.id = 0, .value = 0},
93 IdAndValue{.id = 0, .value = 1},
94 IdAndValue{.id = 0, .value = 2},
95 IdAndValue{.id = 1, .value = 0},
96 IdAndValue{.id = 1, .value = 1},
97 IdAndValue{.id = 1, .value = 2},
98 IdAndValue{.id = 2, .value = 0},
99 IdAndValue{.id = 2, .value = 1},
100 IdAndValue{.id = 2, .value = 2},
101 },
102 []IdAndValue {
103 IdAndValue{.id = 0, .value = 2},
104 IdAndValue{.id = 0, .value = 1},
105 IdAndValue{.id = 0, .value = 0},
106 IdAndValue{.id = 1, .value = 2},
107 IdAndValue{.id = 1, .value = 1},
108 IdAndValue{.id = 1, .value = 0},
109 IdAndValue{.id = 2, .value = 2},
110 IdAndValue{.id = 2, .value = 1},
111 IdAndValue{.id = 2, .value = 0},
112 },
113 };
114 for (cases) |*case| {
115 sort_stable(IdAndValue, (*case)[0..], cmpByValue);
116 for (*case) |item, i| {
117 assert(item.id == expected[i].id);
118 assert(item.value == expected[i].value);
119 }
120 }
121}
122const IdAndValue = struct {
123 id: i32,
124 value: i32,
125};
126fn cmpByValue(a: &const IdAndValue, b: &const IdAndValue) -> Cmp {
127 return i32asc(a.value, b.value);
128}
129
61test "testSort" {130test "testSort" {
62 const u8cases = [][]const []const u8 {131 const u8cases = [][]const []const u8 {
63 [][]const u8{"", ""},132 [][]const u8{"", ""},