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Posted 2023-02-28 wangjian_an

package cn.hncu.search.dfs;

public class dfs 
    public static void main(String[] args) 
        char[] chs='a','b','c','d';
        int start=0;
        int end=chs.length-1;
        dfs(chs,start,end);
    

    private static void dfs(char[] chs, int start, int end) 
        if(start==end+1)
            System.out.println(chs);
        else
            for(int i=start;i<=end;i++)
                swap(chs, start, i);
                dfs(chs, i+1, end);
                swap(chs, start, i);
            
        
    

    private static void swap(char[] chs, int start, int i) 
        char temp=chs[start];
        chs[start]=chs[i];
        chs[i]=temp;