[C/C++] 1042 Shuffling Machine (20 分)

1042 Shuffling Machine (20 分)

Shuffling is a procedure used to randomize a deck of playing cards. Because standard shuffling techniques are seen as weak, and in order to avoid “inside jobs” where employees collaborate with gamblers by performing inadequate shuffles, many casinos employ automatic shuffling machines. Your task is to simulate a shuffling machine.

The machine shuffles a deck of 54 cards according to a given random order and repeats for a given number of times. It is assumed that the initial status of a card deck is in the following order:

S1, S2, …, S13,
H1, H2, …, H13,
C1, C2, …, C13,
D1, D2, …, D13,
J1, J2

where “S” stands for “Spade”, “H” for “Heart”, “C” for “Club”, “D” for “Diamond”, and “J” for “Joker”. A given order is a permutation of distinct integers in [1, 54]. If the number at the i-th position is j, it means to move the card from position i to position j. For example, suppose we only have 5 cards: S3, H5, C1, D13 and J2. Given a shuffling order {4, 2, 5, 3, 1}, the result will be: J2, H5, D13, S3, C1. If we are to repeat the shuffling again, the result will be: C1, H5, S3, J2, D13.

Input Specification:
Each input file contains one test case. For each case, the first line contains a positive integer K (≤20) which is the number of repeat times. Then the next line contains the given order. All the numbers in a line are separated by a space.

Output Specification:
For each test case, print the shuffling results in one line. All the cards are separated by a space, and there must be no extra space at the end of the line.

Sample Input:

2
36 52 37 38 3 39 40 53 54 41 11 12 13 42 43 44 2 4 23 24 25 26 27 6 7 8 48 49 50 51 9 10 14 15 16 5 17 18 19 1 20 21 22 28 29 30 31 32 33 34 35 45 46 47

Sample Output:

S7 C11 C10 C12 S1 H7 H8 H9 D8 D9 S11 S12 S13 D10 D11 D12 S3 S4 S6 S10 H1 H2 C13 D2 D3 D4 H6 H3 D13 J1 J2 C1 C2 C3 C4 D1 S5 H5 H11 H12 C6 C7 C8 C9 S2 S8 S9 H10 D5 D6 D7 H4 H13 C5

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有不认识的词没关系，前边的描述不重要，重要的是我加粗的那句话，再配合给出的例子，就能明白题意了
刚开始我想的是，建立一个数组，数组元素是结构体，用结构体来表示"S1"等，数组有55个，把它们初始化（麻烦），然后执行操作。就发现，不对。

记住，做数组类的题目，要充分利用数组下标的作用。
现在，把1~54，当成54张牌，当输出的时候要转回"大写字母+数字"的形式。
card数组

0	1	2	3	4
S	H	C	D	J
1~13	14~26	27~39	40~52	53~54

转成字母时：(x-1)/13作card[]下标；为什么要-1呢？因为，当x=13，13/13->1,而13所属S，表示为0，而不是1(H)；对于26，39，52同理。
转成数字时：一直是1~13的循环，所以就想到%13，但是又要注意，单纯%13的结果，当x=13的倍数时，结果就是0，而不是13，所以要(x-1)%13+1

下标表示牌
start[]表示初始牌序：i排在第 start[i] 位
next[]表示移动一次后的牌序：i排在第 nextt[i] 位
end[]表示规整后的排序，同时作为下一次的start[]:第i位是end[i](哪张牌)

第	1	2	3	4	···	52	53	54
牌	1	2	3	4	···	52	53	54

牌	1	2	3	4	···	52	53	54
第	35	52	37	38	···	45	46	47

第	1	2	3	4	···	52	53	54
牌	40	17	5	18	···	2	8	9

过程：
第i个牌是start[i]
牌i要放到next[i]的位置
第i个牌是end[i]

#include<stdio.h>

int main()
{
	const int n =54;
	char card[5] = { 'S', 'H', 'C', 'D', 'J'};
	int start[n+1], next[n+1], end[n+1];
	int k;
	scanf("%d",&k);
	for(int i=1;i<=n;i++){
		start[i] = i;
	} 
	for(int i=1;i<=n;i++){
		scanf("%d",&next[i]);
	}
	for(int i=0; i<k; i++){
		for(int j=1; j<=n; j++){
			end[next[j]] = start[j];//注意这里是start[j]而不是j,因为，不止一轮操作 
		}
		for(int i=1;i<=n;i++){
		start[i] = end[i];
		}
	} 
	
	for(int i=1; i<=n; i++){
		printf("%c%d", card[(start[i]-1)/13], (start[i]-1)%13+1);
		if(i<n) printf(" ");	
	}
	
	return 0;
}