java_组合算法类下载(用递归实现)_

package arithmetic;

import java.util.ArrayList;
import java.util.List;

public class MyComposite {
	static int level=-1;
	static int count = 1;
	static int selected = 3;
	public static void main(String[] args){
		char buf[]={'a','b','c','d'}; 
		List container = new ArrayList();
		composite(container,buf,0,buf.length);
	}
	public static void composite(List container,char buf[],int start,int end){
		if(container.size()== selected){
			for(int i=0;i<container.size();i ){
				System.out.print(container.get(i));
			}
			System.out.println();
			if(level>=selected-1){
				level =selected-1;
			}
			System.out.println(count);
			count ;
		}else{
			if(start>=end){
				level--;
			}else{
				for(int i=start;i<end;i ){
					if(level == -1){
						level = 0;
					}
					for(int m=0;m<selected-(level);m ){
						if(container.size()>=selected-m){
							container.remove(selected-1-m);
						}
					}
					level ;
					container.add(buf[i]);
					composite(container,buf,i 1,end);
					if(i 1>=end){
						level--;
					}
					
					
				}
			}
		}
	}
}