mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-11-05 14:03:45 +00:00
149 lines
3.2 KiB
Go
149 lines
3.2 KiB
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
||
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
||
|
||
package word
|
||
|
||
import (
|
||
"fmt"
|
||
"math/rand"
|
||
"time"
|
||
)
|
||
|
||
//!+bench
|
||
|
||
import "testing"
|
||
|
||
//!-bench
|
||
|
||
//!+test
|
||
func TestIsPalindrome(t *testing.T) {
|
||
var tests = []struct {
|
||
input string
|
||
want bool
|
||
}{
|
||
{"", true},
|
||
{"a", true},
|
||
{"aa", true},
|
||
{"ab", false},
|
||
{"kayak", true},
|
||
{"detartrated", true},
|
||
{"A man, a plan, a canal: Panama", true},
|
||
{"Evil I did dwell; lewd did I live.", true},
|
||
{"Able was I ere I saw Elba", true},
|
||
{"été", true},
|
||
{"Et se resservir, ivresse reste.", true},
|
||
{"palindrome", false}, // non-palindrome
|
||
{"desserts", false}, // semi-palindrome
|
||
}
|
||
for _, test := range tests {
|
||
if got := IsPalindrome(test.input); got != test.want {
|
||
t.Errorf("IsPalindrome(%q) = %v", test.input, got)
|
||
}
|
||
}
|
||
}
|
||
|
||
//!-test
|
||
|
||
//!+bench
|
||
func BenchmarkIsPalindrome(b *testing.B) {
|
||
for i := 0; i < b.N; i++ {
|
||
IsPalindrome("A man, a plan, a canal: Panama")
|
||
}
|
||
}
|
||
|
||
//!-bench
|
||
|
||
//!+example
|
||
|
||
func ExampleIsPalindrome() {
|
||
fmt.Println(IsPalindrome("A man, a plan, a canal: Panama"))
|
||
fmt.Println(IsPalindrome("palindrome"))
|
||
// Output:
|
||
// true
|
||
// false
|
||
}
|
||
|
||
//!-example
|
||
|
||
/*
|
||
//!+random
|
||
import "math/rand"
|
||
|
||
//!-random
|
||
*/
|
||
|
||
//!+random
|
||
// randomPalindrome returns a palindrome whose length and contents
|
||
// are derived from the pseudo-random number generator rng.
|
||
func randomPalindrome(rng *rand.Rand) string {
|
||
n := rng.Intn(25) // random length up to 24
|
||
runes := make([]rune, n)
|
||
for i := 0; i < (n+1)/2; i++ {
|
||
r := rune(rng.Intn(0x1000)) // random rune up to '\u0999'
|
||
runes[i] = r
|
||
runes[n-1-i] = r
|
||
}
|
||
return string(runes)
|
||
}
|
||
|
||
func TestRandomPalindromes(t *testing.T) {
|
||
// Initialize a pseudo-random number generator.
|
||
seed := time.Now().UTC().UnixNano()
|
||
t.Logf("Random seed: %d", seed)
|
||
rng := rand.New(rand.NewSource(seed))
|
||
|
||
for i := 0; i < 1000; i++ {
|
||
p := randomPalindrome(rng)
|
||
if !IsPalindrome(p) {
|
||
t.Errorf("IsPalindrome(%q) = false", p)
|
||
}
|
||
}
|
||
}
|
||
|
||
//!-random
|
||
|
||
/*
|
||
// Answer for Exercicse 11.1: Modify randomPalindrome to exercise
|
||
// IsPalindrome's handling of punctuation and spaces.
|
||
|
||
// WARNING: the conversion r -> upper -> lower doesn't preserve
|
||
// the value of r in some cases, e.g., µ Μ, ſ S, ı I
|
||
|
||
// randomPalindrome returns a palindrome whose length and contents
|
||
// are derived from the pseudo-random number generator rng.
|
||
func randomNoisyPalindrome(rng *rand.Rand) string {
|
||
n := rng.Intn(25) // random length up to 24
|
||
runes := make([]rune, n)
|
||
for i := 0; i < (n+1)/2; i++ {
|
||
r := rune(rng.Intn(0x200)) // random rune up to \u99
|
||
runes[i] = r
|
||
r1 := r
|
||
if unicode.IsLetter(r) && unicode.IsLower(r) {
|
||
r = unicode.ToUpper(r)
|
||
if unicode.ToLower(r) != r1 {
|
||
fmt.Printf("cap? %c %c\n", r1, r)
|
||
}
|
||
}
|
||
runes[n-1-i] = r
|
||
}
|
||
return "?" + string(runes) + "!"
|
||
}
|
||
|
||
func TestRandomNoisyPalindromes(t *testing.T) {
|
||
// Initialize a pseudo-random number generator.
|
||
seed := time.Now().UTC().UnixNano()
|
||
t.Logf("Random seed: %d", seed)
|
||
rng := rand.New(rand.NewSource(seed))
|
||
|
||
n := 0
|
||
for i := 0; i < 1000; i++ {
|
||
p := randomNoisyPalindrome(rng)
|
||
if !IsPalindrome(p) {
|
||
t.Errorf("IsNoisyPalindrome(%q) = false", p)
|
||
n++
|
||
}
|
||
}
|
||
fmt.Fprintf(os.Stderr, "fail = %d\n", n)
|
||
}
|
||
*/
|