问题描述:根据输入m数据,找出str的m个字符的所有字符串
例如"abc" m=2
"ab" "ac" "bc"
"abcd" m=3
例如"abc" m=2
"ab" "ac" "bc"
"abcd" m=3
"abc" "acd" "bcd" "abd"
在此为了简便,直接用把字符串和m 写死。
import java.util.ArrayList;
/**
* @author yanwu
*
*/
public class Test03
{
public static void main(String[] args)
{
perenum("abc", 2);
}
public static ArrayList<String> perenum(String str,int m)
{
find("",str, m);
return null;
}
public static String find(String strBef,String str,int m)
{
ArrayList<String> strArr = new ArrayList<String>();
for(int i=0; i <str.length(); i++)
{
String allstr = strBef + str.charAt(i);
String str1 = str.substring(i + 1);
find(allstr,str1, m);
strArr.add(allstr);
if (allstr.length() == m)
{
System.out.print(allstr + " ");
}
}
return str;
}
}