PAT 解题报告 1042. Shuffling Machine (20)

1042. Shuffling Machine 题目描述:

题目要求模拟自动洗牌机器(Shuffling Machine)的洗牌过程过程, 比如用数组S表示Shuffling Machine, S[i] = j表示第i张卡要被放到第j个位置. 更具体的描述如下:

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.

1042. Shuffling Machine 算法分析:

用两个数组模拟洗牌前的顺序以及洗牌后的顺序, 要洗K次牌, 洗完以后输出结果, 基本上是一个直接模拟的过程, 没什么难度。

#include <algorithm>
#include <string>
#include <vector>
#include <map>
#define REP(i,n) for(int i=0;i<(n);++i)

using namespace std;

string int2string[54];

void gao(int k, int per[]) {
    REP(i, 54) {
        ostringstream c("");
        if(i / 13 == 0) c << "S";
        if(i / 13 == 1) c << "H";
        if(i / 13 == 2) c << "C";
        if(i / 13 == 3) c << "D";
        if(i / 13 == 4) c << "J";
        c << i%13+1;
        int2string[i] = c.str();
    int cards[54];
    int cards2[54];
    REP(i, 54) cards[i] = i;
    memcpy(cards2, cards, sizeof(cards));
    while(k--) {
        REP(i, 54) {
            cards2[per[i]-1] = cards[i];
        memcpy(cards, cards2, sizeof(cards));
    REP(i, 54) {
        if(!i) cout<<int2string[cards2[i]];
        else cout<<" "<<int2string[cards[i]];

int main(void) {
    int K;
    int permute[54];
    REP(i, 54) cin>>permute[i];
    gao(K, permute);
    return 0;
Written on January 18, 2014