题解 | 字符串的排列

package main

import "sort"

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param str string字符串
 * @return string字符串一维数组
 */
func Permutation( str string ) []string {
    // write code here
    var tmp []byte
    used := make([]bool, len(str))
    var res []string
    str = SortStr(str)
    solve(str, tmp, used, &res)

    return res
}

func SortStr(str string) string {
    runeStr := []byte(str)
    sort.Slice(runeStr, func(i, j int) bool{
        return str[i] < str[j]
    })
    
    return string(runeStr)
}

func solve (str string, tmp []byte, used []bool, res *[]string){
    if len(tmp) == len(str){
        xx := make([]byte, len(tmp))
        copy(xx, tmp)
        *res = append(*res, string(xx))

        // *res = append(*res, string(tmp))
        return
    }

    for i:=0; i<len(str);i++{
        if used[i] == true{
            continue
        }
        if i>0 && str[i] == str[i-1] && used[i-1] == false{
            continue
        }

        used[i] = true
        tmp = append(tmp, str[i])
        solve(str, tmp, used, res)
        used[i] = false
        tmp = tmp[:len(tmp)-1]
    }
}