In Golang string is a sequence of bytes. A string literal actually represents a UTF-8 sequence of bytes. In UTF-8, ASCII characters are single-byte corresponding to the first 128 Unicode characters. All other characters are between 1 -4 bytes. Due to this, it is not possible to index a character in a string. In GO, rune data type represents a Unicode point. Once a string is converted to an array of rune then it is possible to index a character in that array of rune.
You can learn more about rune here – /understanding-rune-in-golang
For this reason in below program for generating permutations we are first converting a string into a rune array so that we can index the rune array to get the individual characters.
package main
import "fmt"
func main() {
sample := "ab£"
sampleRune := []rune(sample)
generatePermutation(sampleRune, 0, len(sampleRune)-1)
}
func generatePermutation(sampleRune []rune, left, right int) {
if left == right {
fmt.Println(string(sampleRune))
} else {
for i := left; i <= right; i++ {
sampleRune[left], sampleRune[i] = sampleRune[i], sampleRune[left]
generatePermutation(sampleRune, left+1, right)
sampleRune[left], sampleRune[i] = sampleRune[i], sampleRune[left]
}
}
}Output:
ab£
a£b
ba£
b£a
£ba
£ab