题解 | #字符串的排列#

import java.util.*;
public class Solution {
    public ArrayList<String> Permutation(String str) {
        ArrayList<String> ans = new ArrayList<>();
        char[] ch = str.toCharArray();
        Arrays.sort(ch);
        boolean[] visited = new boolean[ch.length];
        Arrays.fill(visited,false);
        callBack(ans,new String(),visited,ch);
        return ans;
        if(path.length() == ch.length){
            ans.add(path);
            return;
        }
        for(int i = 0;i<ch.length;i++){
            if(visited[i]){
                continue;
            }
            if(i>0 && ch[i] == ch[i-1]&&!visited[i-1]){
                continue;
            }
            path = path + ch[i];
            int length = path.length();
            visited[i] = true;
            callBack(ans,path,visited,ch);
            visited[i] = false;
            path = path.substring(0,length-1);
        }
    }
}