C++扑克牌随机洗牌抽牌算法

题目
算法思想
代码解析
完整代码

题目

4个人甲乙丙丁一起玩扑克牌，其中1-10各种花色纸牌分别为1-10，J、Q、K被记为11、12、13，大王小王都记为20.四种花色（方块、梅花、红桃、黑桃）分别被记为A、B、C、D。如红桃K表示为13C，分值13；方块5表示为5A，分值5；大王表示为20K，分值20；小王表示为20Q，分值20。
游戏过程如下：
1、洗牌：54张牌随机组合
2、4人排序：随机产生4人的拿牌顺序，拿牌顺序与出牌顺序相同。
3、分派：按拿牌顺序每人轮流拿牌，每人拿13张，最后两张留在桌面。
4、出牌：从第一个拿牌的人开始出牌（随即出牌），每一轮4人出牌，牌最大的获取当前轮次的四张牌。大小判定规则，纸牌分值大>纸牌分值小，相同指派分值，按照黑桃>红桃>梅花>方块。

算法思想

洗牌、四人排序以及随机出牌都是随机且不重复抽取。如果用随机函数直接随机生成数字然后再判定是否重复，这样算法复杂且时间复杂度高，可以逆向思考为生成一个随机排列的序号数组，然后顺序输出随机排列的序号数组。
牌面的大小判定可以先用一个循环判定数字大小，然后因为由字符的ASCII码值判定花色大小。

代码解析

构建对象Player(玩家)
Player的属性有名字、手中拥有的牌、出牌顺序、分数；
构造函数,在玩家对象被声明的时候，就要赋予玩家名字，将其分数置为0

 Player(string name) //构造函数{p_name = name;p_score = 0;}

对象声明

//玩家
class Player
{private:string p_name;    //玩家的名字int p_card_index[13];    //牌面的序号vector<int> p_s_index;  //随机的出牌顺序int p_score;  //玩家的得分
public:Player(string name) //构造函数{p_name = name;p_score = 0;}string getName(){return p_name;};  //      查看名字void saveCard(int n,int i){p_card_index[n] = i;};       //将第n轮分到了序号为i的牌保存下来int getCard(int i);   //第i轮随机出牌。输出出牌序号int showCard(int i){return p_card_index[i];}   //第i轮分到的牌void addScore(int s){p_score += s;};   //分数增加s分int getScore(){return p_score;};    //查看此时的分数
};

C++11的标准库中有一个函数shuffle()
函数原型：

template <class RandomAccessIterator, class URNG>
void shuffle (RandomAccessIterator first, RandomAccessIterator last, URNG&& g);

函数功能：
使用随机生成器g对元素[first, last)的容器内部元素进行随机排列
函数参数：

first, last	g
顺序容器迭代器的开头和结尾	随机数生成器的一个实例

card_index.push_back(i)，向容器末尾添加新元素i。
seed = chrono::system_clock::now().time_since_epoch().count()，用seed来初始化生成器，避免出现重复的排列。

#include <algorithm> // std::move_backward
#include <random> // std::default_random_engine
#include <chrono> // std::chrono::system_clock//将扑克牌顺序打乱
void rand_cards(vector<int>& card_index) //洗牌
{for(int i=0; i<54; i++)card_index.push_back(i);//card_index[i]=i;unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(card_index.begin(),card_index.end(),default_random_engine(seed));}void rand_players(vector<int>& s_players)  //四人排序
{for(int i=0; i<4; i++)s_players.push_back(i);unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(s_players.begin(),s_players.end(),default_random_engine(seed));}
int Player::getCard(int i)//对象的成员函数，生成每个玩家的随机出牌顺序
{for(int i=0; i<13; i++)p_s_index.push_back(i);unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(p_s_index.begin(),p_s_index.end(),default_random_engine(seed));return p_card_index[p_s_index[i]];//根据生成的顺序从自己所拥有的牌中抽取
}

分牌，将打乱顺序的牌按照之间随机的四人分派顺序分配给玩家。

void deal_cards(Player* p,vector<int> s_players,vector<int> card_index)//分牌
{int t=0;  //记录轮次for(int i=0; i<52; i++){if(i%4==0&&i!=0)//每过4人就到了下一轮t++;p[s_players[i%4]].saveCard(t,card_index[i]);}}

玩家出牌并比较各自的牌大小，最大的拿分

void play_cards(Player* p) //出牌
{for(int i=0;i<13;i++){int win = Compare_cards(i,p);   //找出第i轮胜利者int score = 0;for(int j=0;j<4;j++)    //算出总分score += getValue(p[j].getCard(i));p[win].addScore(score);}
}int Compare_cards(int i,Player p[])//比较第i轮四个人谁赢
{int p_num[4];   //四个人第i轮的牌面序号for(int j=0; j<4; j++)p_num[j] = p[j].getCard(i);int maxp[4]= {1,0,0,0}; //假设最大的是第一个人int maxj=0;for(int j=1; j < 4; j++) //选出数字最大者{if(getValue(p_num[j]) > getValue(p_num[maxj]))//若比最大者大，则更改记录{ maxp[maxj] = 0;maxp[j] = 1;maxj = j;}else if(getValue(p_num[j]) == getValue(p_num[maxj]))//若相等，则加入记录maxp[j] = 1;}for(int j=0; j<4; j++) //选出字母最大者if(maxp[j]){int bigger = Bigger_pattern(p_num[j], p_num[maxj]);if(p_num[j] == bigger)maxj = j;}return maxj;
}int Bigger_pattern(int a,int b)   //a,b为花色序号,只比较花色
{string a_s,b_s;    //序号转化为牌面a_s = cards[a];b_s = cards[b];char a_ch,b_ch;//牌面转化为花色a_ch = a_s[a_s.length()-1];b_ch = b_s[b_s.length()-1];switch(a_ch)//花色为K、Q单独讨论，为A~D直接用ASCII码计算{case 'K':return a;case 'Q':if(b_ch=='K')return b;elsereturn a;case 'D':case 'C':case 'B':case 'A':return (a_ch-b_ch)?a:b;default:cout<<"pattern error"<<endl;break;}
}

完整代码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<random>
#include<chrono>using namespace std;
//卡牌
const string cards[54] {"1A","2A","3A","4A","5A","6A","7A","8A","9A","10A","11A","12A","13A","1B","2B","3B","4B","5B","6B","7B","8B","9B","10B","11B","12B","13B","1C","2C","3C","4C","5C","6C","7C","8C","9C","10C","11C","12C","13C","1D","2D","3D","4D","5D","6D","7D","8D","9D","10D","11D","12D","13D","20K","20Q"};//玩家
class Player
{private:string p_name;//玩家的名字int p_card_index[13];//牌面的序号vector<int> p_s_index;//随机的出牌顺序int p_score;//玩家的得分
public:Player(string name) //构造函数{p_name = name;p_score = 0;};string getName(){return p_name;};//查看名字void saveCard(int n,int i){p_card_index[n] = i;};//第n轮分到了序号为i的牌int getCard(int i);//第i轮出牌序号int showCard(int i){return p_card_index[i];};//第i轮拿到的牌void addScore(int s){p_score += s;};//分数增加s分int getScore(){return p_score;};//查看此时的分数
};int getValue(int i);//将卡牌序号转化为分数
int Compare_cards(int i,Player* p_play);//比较第i轮四个人谁赢
int Bigger_pattern(int a,int b);//两个花色比较
int win_player(Player p[]);//最终胜利的人void rand_cards(vector<int>& card_index);//洗牌
void rand_players(vector<int>& s_players);//四人排序
void deal_cards(Player* p,vector<int> s_players,vector<int> card_index);//分牌
void play_cards(Player* p);//出牌
void show(Player p_play[4]);//展示结果int main()
{Player p_play[4]={Player("甲"),Player("乙"),Player("丙"),Player("丁")};//四个人玩vector<int> card_index;//54张牌vector<int> s_players;//四人分牌顺序rand_players(s_players);//四人排序rand_cards(card_index);//洗牌deal_cards(p_play,s_players,card_index);//分牌play_cards(p_play);//出牌show(p_play);//展示结果return 0;
}int getValue(int i)//将卡牌序号转化为分数
{string s = cards[i];int value = 0;for(int i = 0; i<s.length()-1; i++)value = value*10 + s[i]-'0';return value;
}int Compare_cards(int i,Player p[])//比较第i轮四个人谁赢
{int p_num[4];   //四个人第i轮的牌面序号for(int j=0; j<4; j++){p_num[j] = p[j].getCard(i);}int maxp[4]= {1,0,0,0}; //假设最大的是第一个人int maxj=0;for(int j=1; j < 4; j++) //选出数字最大者{if(getValue(p_num[j]) > getValue(p_num[maxj])){maxp[maxj] = 0;maxp[j] = 1;maxj = j;}else if(getValue(p_num[j]) == getValue(p_num[maxj]))maxp[j] = 1;}//选出字母最大者for(int j=0; j<4; j++)if(maxp[j]){int bigger = Bigger_pattern(p_num[j], p_num[maxj]);if(p_num[j] == bigger)maxj = j; }return maxj;
}int Bigger_pattern(int a,int b)   //a,b为花色序号,只比较花色
{string a_s,b_s;a_s = cards[a];b_s = cards[b];char a_ch,b_ch;a_ch = a_s[a_s.length()-1];b_ch = b_s[b_s.length()-1];switch(a_ch){case 'K':return a;case 'Q':if(b_ch=='K')return b;elsereturn a;case 'D':case 'C':case 'B':case 'A':return (a_ch-b_ch)?a:b;default:cout<<"pattern error"<<endl;break;}
}int win_player(Player p[]) //最终胜利的人
{int maxi=0,maxScore=p[0].getScore();    //假设第一个人是最终胜利者for(int i=1;i<4;i++){int score = p[i].getScore();if(score > maxScore){ maxScore = score;maxi = i;}}return maxi;
}void rand_cards(vector<int>& card_index) //洗牌
{for(int i=0; i<54; i++)card_index.push_back(i);unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(card_index.begin(),card_index.end(),default_random_engine(seed));
}void rand_players(vector<int>& s_players)  //四人排序
{for(int i=0; i<4; i++)s_players.push_back(i);unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(s_players.begin(),s_players.end(),default_random_engine(seed));
}void deal_cards(Player* p,vector<int> s_players,vector<int> card_index) //分牌
{int t=0;for(int i=0; i<52; i++){if(i%4==0&&i!=0)t++;p[s_players[i%4]].saveCard(t,card_index[i]);}
}void play_cards(Player* p) //出牌
{for(int i=0;i<13;i++){int win = Compare_cards(i,p);   //找出第i轮胜利者int score = 0;for(int j=0;j<4;j++)    //算出总分score += getValue(p[j].getCard(i));p[win].addScore(score);}
}void show(Player p[4])  //展示结果
{for(int i = 0;i<4;i++){cout<<p[i].getName();for(int j = 0;j<13;j++){cout<<cards[p[i].showCard(j)];if(j==12)cout<<endl;else cout<<" , ";}}cout<<"得分："<<endl;for(int i =0;i<4;i++)cout<<p[i].getName()<<" "<<p[i].getScore()<<endl;cout<<"得分最多："<<p[win_player(p)].getName();}int Player::getCard(int i)//生成随机出牌顺序
{for(int i=0; i<13; i++)p_s_index.push_back(i);unsigned seed = chrono::system_clock::now().time_since_epoch().count();shuffle(p_s_index.begin(),p_s_index.end(),default_random_engine(seed));return p_card_index[p_s_index[i]];
}