재 귀 알고리즘 자바 구현(공,전체 배열,반전 꼬치,양 휘 삼각형,AB 조합)

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt(),b=sc.nextInt();
        int an=find(a,b);
        System.out.println(an);
    }
    public static int find(int a,int b){
        if(areturn 0;
        if(a==b) return 1;
        if(b==0) return 1; 
        return find(a-1,  b-1)+find(a-1, b);
    }
}

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc=new Scanner(System.in);
        String s=sc.nextLine();
        char[] a=s.toCharArray();
        find(a, 0);
    }
    public static void find(char[] a,int k){
        if(k==a.length){
            for(int i=0;iout.print(a[i]+" ");
            }
            System.out.println();
        } 
        for(int i=k;ichar t=a[k];a[k]=a[i];a[i]=t;
            find(a, k+1);
             t=a[k];a[k]=a[i];a[i]=t;
        }
    }
}

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String sc="abc";
        System.out.println(find(sc));
    }
    public static String find(String s){
        if(s==null||s.length()<2) return s;
        return  s.substring(1) +s.charAt(0);
    }
}

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scanner=new Scanner(System.in);
        int m=scanner.nextInt();
        int n=scanner.nextInt();
        System.out.println(find(m,n));
    }
    public static int find(int m,int n){
        if(m==0) return 1;
        if(m==n) return 1;
        return find(m-1, n)+find(m-1,n-1);
    }
}

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scanner=new Scanner(System.in);
        int m=scanner.nextInt();
        int n=scanner.nextInt();
        System.out.println(find(m,n));
    }
    public static int find(int m,int n){
        if(m==0||n==0) return 1;
        return find(m-1, n)+find(m,n-1);
    }
}