第六届河南省程序设计大赛——F Card Trick

清疚 2022-04-24 22:34 195阅读 0赞

## 题目描述: ##

The magician shuffles a small pack of cards, holds it face down and performs the following procedure:

1.  The top card is moved to the bottom of the pack. The new top card is dealt face up onto the table. It is the Ace of Spades.
2.  Two cards are moved one at a time from the top to the bottom. The next card is dealt face up onto the table. It is the Two of Spades.
3.  Three cards are moved one at a time…
4.  This goes on until the *n*th and last card turns out to be the *n* of Spades.

This impressive trick works if the magician knows how to arrange the cards beforehand (and knows how to give a false shuffle). Your program has to determine the initial order of the cards for a given number of cards, 1 ≤ n ≤ 13.

## 输入描述: ##

<span style="color:#000000">On the first line of the input is a single positive integer k, telling the number of test cases to follow. 1 ≤ k ≤ 10  Each case consists of one line containing the integer n.  1 ≤ n ≤ 13</span>

## 输出描述: ##

<span style="color:#000000">For each test case, output a line with the correct permutation of the values 1 to n, space separated. The first number showing the top card of the pack, etc…</span>

## 样例输入: ##

复制

2
    4
    5

## 样例输出: ##

2 1 4 3
    3 1 4 5 2

找规律就行，样例输入4

取牌的顺序为如下：

![20190429225607547.jpg][]

1退出之前将一张牌放到最后也就是2，

2退出之前将两张牌放到最后也就是4 3

3退出之前将三张牌放到最后也就是4 3 4

4退出时由于只剩这一张牌了所以直接退出就行

按照这个规律从退出n倒推到退出1

ac代码：

#include<iostream>
    #include<cstdio>
    #include<algorithm>
    #include<cstring>
    #include<cmath>
    using namespace std;
    int main(){
    	int t,book[1005];
    	cin>>t;
    	while(t--){
    		fill(book,book+1005,0);
    		int n,l=0,r=2;
    		cin>>n;
    		book[0]=n;book[1]=n-1;  //因为最后两个数肯定是n和n-1 
    		for(int i=n-1;i>0;i--){
    			int j=i;
    			while(j--){ //循环j次 
    				book[r++]=book[l++];
    			}
    			if(i!=1)book[r++]=i-1;  //循环之后加上退出的 
    		}
    		for(int i=r-1;i>r-1-n;i--){
    			cout<<book[i]<<" ";
    		}
    		cout<<endl;
    	}
    	return 0;
    }

[20190429225607547.jpg]: /images/20220212/f85f3a79357b4ea99d27efe1f83e690b.png