poj2083



Fractal

Time Limit: 1000MS  Memory Limit: 30000K
Total Submissions: 8604  Accepted: 4081

Description

A fractal is an object or quantity that displays self-similarity, in a somewhat technical sense, on all scales. The object need not exhibit exactly the same structure at all scales, but the same "type" of structures must appear on all scales.
A box fractal is defined as below :
•A box fractal of degree 1 is simply
X

• A box fractal of degree 2 is
X X
X
X X

•If using B(n - 1) to represent the box fractal of degree n - 1, then a box fractal of degree n is defined recursively as following
B(n - 1)        B(n - 1)

        B(n - 1)

B(n - 1)        B(n - 1)

Your task is to draw a box fractal of degree n.
Input

The input consists of several test cases. Each line of the input contains a positive integer n which is no greater than 7. The last line of input is a negative integer −1 indicating the end of input.

Output

For each test case, output the box fractal using the 'X' notation. Please notice that 'X' is an uppercase letter. Print a line with only a single dash after each test case.

Sample Input
1
2
3
4
-1

Sample Output
X
-
X X
 X
X X
-
X X   X X
 X     X
X X   X X
   X X
    X
   X X
X X   X X
 X     X
X X   X X
-
X X   X X         X X   X X
 X     X           X     X
X X   X X         X X   X X
   X X               X X
    X                 X
   X X               X X
X X   X X         X X   X X
 X     X           X     X
X X   X X         X X   X X
         X X   X X
          X     X
         X X   X X
            X X
             X
            X X
         X X   X X
          X     X
         X X   X X
X X   X X         X X   X X
 X     X           X     X
X X   X X         X X   X X
   X X               X X
    X                 X
   X X               X X
X X   X X         X X   X X
 X     X           X     X
X X   X X         X X   X X
-

Source

 代码：

#include<iostream>
#include<string.h>
#include<map>
#include<cmath>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
using namespace std;
char a[800][800];
void dfs(int n,int x,int y)
{
    if(n==1)
    {
        a[x][y]='X';
        return ;
    }
    else
    {
        int size=pow(3,n-2);
        dfs(n-1,x,y);
        dfs(n-1,x+size+size,y);
        dfs(n-1,x+size,y+size);
        dfs(n-1,x,y+size+size);
        dfs(n-1,x+size+size,y+size+size);
    }
}
int main()
{
    int t;
    while(cin>>t)
    {
        if(t<=0)
            break;
        int size=pow(3,t-1);
        for(int i=0;i<size;i++)
        {
            for(int j=0;j<size;j++)
            {
                a[i][j]=' ';
            }
        }
        dfs(t,0,0);
         for(int i=0;i<size;i++)
        {
            a[i][size]='\0';
        }
         for(int i=0;i<size;i++)
        {
            puts(a[i]);
        }
        printf("-\n");
    }
}