Commit 18852cf6 authored by Robert Griesemer's avatar Robert Griesemer

- added sort package and test case

R=r
OCL=14975
CL=14975
parent c3ca0561
......@@ -7,7 +7,7 @@
echo; echo; echo %%%% making lib %%%%; echo
rm -f *.6
for i in fmt.go flag.go container/vector.go
for i in fmt.go flag.go container/vector.go sort.go
do
base=$(basename $i .go)
echo 6g -o $GOROOT/pkg/$base.6 $i
......
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package Sort
export type SortInterface interface {
len() int;
less(i, j int) bool;
swap(i, j int);
}
func Pivot(data SortInterface, a, b int) int {
// if we have at least 10 elements, find a better median
// by selecting the median of 3 elements and putting it
// at position a
if b - a >= 10 {
m0 := (a + b) / 2;
m1 := a;
m2 := b - 1;
// bubble sort on 3 elements
if data.less(m1, m0) { data.swap(m1, m0); }
if data.less(m2, m1) { data.swap(m2, m1); }
if data.less(m1, m0) { data.swap(m1, m0); }
// "m0 <= m1 <= m2"
}
m := a;
for i := a + 1; i < b; i++ {
if data.less(i, a) {
m++;
data.swap(i, m);
}
}
data.swap(a, m);
return m;
}
func Quicksort(data SortInterface, a, b int) {
if a + 1 < b {
m := Pivot(data, a, b);
Quicksort(data, 0, m);
Quicksort(data, m + 1, b);
}
}
export func Sort(data SortInterface) {
Quicksort(data, 0, data.len());
}
export func IsSorted(data SortInterface) bool {
n := data.len();
for i := n - 1; i > 0; i-- {
if data.less(i, i - 1) {
return false;
}
}
return true;
}
// Convenience types for common cases
// TODO: Once we can associate methods with all types, this can be simplified
// since we cann associate the methods with the arrays directly.
export type IntArray struct {
data *[]int;
}
func (p *IntArray) len() int { return len(p.data); }
func (p *IntArray) less(i, j int) bool { return p.data[i] < p.data[j]; }
func (p *IntArray) swap(i, j int) { p.data[i], p.data[j] = p.data[j], p.data[i]; }
export type FloatArray struct {
data *[]float;
}
func (p *FloatArray) len() int { return len(p.data); }
func (p *FloatArray) less(i, j int) bool { return p.data[i] < p.data[j]; }
func (p *FloatArray) swap(i, j int) { p.data[i], p.data[j] = p.data[j], p.data[i]; }
export type StringArray struct {
data *[]string;
}
func (p *StringArray) len() int { return len(p.data); }
func (p *StringArray) less(i, j int) bool { return p.data[i] < p.data[j]; }
func (p *StringArray) swap(i, j int) { p.data[i], p.data[j] = p.data[j], p.data[i]; }
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// $G $F.go && $L $F.$A && ./$A.out
package main
import Sort "sort"
func main() {
{ data := []int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586};
a := Sort.IntArray(&data);
Sort.Sort(&a);
/*
for i := 0; i < len(data); i++ {
print(data[i], " ");
}
print("\n");
*/
if !Sort.IsSorted(&a) {
panic();
}
}
{ data := []float{74.3, 59.0, 238.2, -784.0, 2.3, 9845.768, -959.7485, 905, 7.8, 7.8};
a := Sort.FloatArray(&data);
Sort.Sort(&a);
/*
for i := 0; i < len(data); i++ {
print(data[i], " ");
}
print("\n");
*/
if !Sort.IsSorted(&a) {
panic();
}
}
{ data := []string{"", "Hello", "foo", "bar", "foo", "f00", "%*&^*&^&", "***"};
a := Sort.StringArray(&data);
Sort.Sort(&a);
/*
for i := 0; i < len(data); i++ {
print(data[i], " ");
}
print("\n");
*/
if !Sort.IsSorted(&a) {
panic();
}
}
}
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