剑指offer-第四章解决面试题思路（字符串的排序）

public class StringPermutation {
    public void permutation(char[] s){
        if(s==null)
            return;
        permutation(s,0);
    }

    public void permutation(char[] s, int begin) {
        if(begin==s.length)
            System.out.println(s);
        else{
            for(int i=begin;i<s.length;i++){
                swrap(s,begin,i);
                permutation(s,begin+1);
                swrap(s,begin,i);
            }
            
        }
    }
    public void swrap(char[] s,int m,int n){
        char temp=s[m];
        s[m]=s[n];
        s[n]=temp;
    }
    public static void main(String[] args){
        char[] s={‘a‘,‘b‘,‘c‘};
        StringPermutation sp=new StringPermutation();
        sp.permutation(s);
    }
}