【PAT甲级真题】- Shuffling Machine (20)

题目来源

Shuffling Machine - PTA
Shuffling Machine - 牛客

Description

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 54 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:

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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 $1 , 54$ $1, 54$ $1,54$ . 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 } \{4, 2, 5, 3, 1\} {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 ) K (≤20) 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:

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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:

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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

题目大意

给定洗牌的次数 k k k 和洗牌的顺序数组 p ，p[i] 表示一次洗牌把第 i

个数放到 p[i] 的位置。保证初始牌序是

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H1, H2, ..., H13, 
C1, C2, ..., C13, 
D1, D2, ..., D13, 
J1, J2

输出经过 k k k 次洗牌后的牌序

思路简介

类似桶排序的思路

首先维护一个洗牌顺序数组 p 用于保存更新的顺序

然后维护两个字符串数组 s,tmp ，其中 s 保存更新前的牌序，tmp 用来保存更新后的牌序

更新时，直接把 s 中对应位置的字符串按照 p 的顺序填入 tmp

最后 tmp=s 即可

注意输入的序号是从 1 开始的，桶下标从 0 0 0 开始，要做对齐处理

遇到的问题

无，一遍过

代码

cpp 复制代码

/**
 * Shuffling Machine
 * https://www.nowcoder.com/pat/5/problem/4081
 * https://pintia.cn/problem-sets/994805342720868352/exam/problems/type/7?problemSetProblemId=994805442671132672
 * 桶排
 */
#include<bits/stdc++.h>
using namespace std;

string card[55];
string tmp[55];
int p[54];
string head[4]={"S","H","C","D"};

void init(){
    int cnt=0;
    for(int i=0;i<4;++i){
        for(int j=1;j<=13;++j){
            card[cnt++]=head[i]+to_string(j);
        }
    }
    card[cnt++]="J1",card[cnt++]="J2";
}

void solve(){
    init();
    int n;cin>>n;
    for(int i=0;i<54;++i)cin>>p[i];
    while(n--){
        for(int i=0;i<54;++i){
            tmp[p[i]-1]=card[i];
        }
        for(int i=0;i<54;++i)
            if(tmp[i]!="")card[i]=tmp[i];
    }
    for(int i=0;i<54;++i){
        cout<<card[i];
        if(i!=53)cout<<' ';
    }
    cout<<'\n';
}

int main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //fstream in("in.txt",ios::in);cin.rdbuf(in.rdbuf());
    int T=1;
    //cin>>T;
    while(T--){
        solve();
    }
    return 0;
}