Commit c5b2bdae11

Steve Perkins <steve@octopart.com>
2016-11-02 23:10:44
quicksort
1 parent e4271f4
Changed files (1)
std/sort.zig
@@ -0,0 +1,65 @@
+const assert = @import("debug.zig").assert;
+const str = @import("str.zig");
+
+pub fn sort(inline T: type, array: []T) {
+    if (array.len > 0) {
+        quicksort(T, array, 0, array.len - 1);
+    }
+}
+
+fn quicksort(inline T: type, array: []T, left: usize, right: usize) {
+    var i = left;
+    var j = right;
+    var p = (i + j) / 2;
+
+    while (i <= j) {
+        while (array[i] < array[p]) {
+            i += 1;
+        }
+        while (array[j] > array[p]) {
+            j -= 1;
+        }
+        if (i <= j) {
+            const tmp = array[i];
+            array[i] = array[j];
+            array[j] = tmp;
+            i += 1;
+            if (j > 0) j -= 1;
+        }
+    }
+
+    if (left < j) quicksort(T, array, left, j);
+    if (i < right) quicksort(T, array, i, right);
+}
+
+fn testSort() {
+    @setFnTest(this, true);
+
+    const u8cases = [][][]u8 {
+        [][]u8{"", ""},
+        [][]u8{"a", "a"},
+        [][]u8{"az", "az"},
+        [][]u8{"za", "az"},
+        [][]u8{"asdf", "adfs"},
+        [][]u8{"one", "eno"},
+    };
+
+    for (u8cases) |case| {
+        sort(u8, case[0]);
+        assert(str.eql(case[0], case[1]));
+    }
+
+    const i32cases = [][][]i32 {
+        [][]i32{[]i32{}, []i32{}},
+        [][]i32{[]i32{1}, []i32{1}},
+        [][]i32{[]i32{0, 1}, []i32{0, 1}},
+        [][]i32{[]i32{1, 0}, []i32{0, 1}},
+        [][]i32{[]i32{1, -1, 0}, []i32{-1, 0, 1}},
+        [][]i32{[]i32{2, 1, 3}, []i32{1, 2, 3}},
+    };
+
+    for (i32cases) |case| {
+        sort(i32, case[0]);
+        assert(str.sliceEql(i32, case[0], case[1]));
+    }
+}