对n个不同字母的全排列

public class Liang {
	
	public static char[] str = {'a','b','c','d','e','f'};
	public static boolean[] visit = new boolean[str.length];
	public static char[] result = new char[str.length];
	public static int total = 0;
	
	public static void main(String[] args) {
		total = 0;
		Arrays.fill(visit, false);
		dfs(0);
		System.out.println(total);
	}
	
	public static void dfs(int level){
		if( level == str.length){
			show();
			total++;
			return;
		}
		for(int i = 0 ; i < str.length; i++){
			if(!visit[i]){
				visit[i] = true;
				result[level] = str[i];
				visit[i] = false;
				dfs(level+1);
				//visit[i] = false;
			}
		}
		return;
	}
	
	public static void show(){
		for(int i = 0; i < result.length; i++){
			System.out.print(result[i]);
		}
		System.out.println();
	}

}