全班隔離期望值＿一般code.cpp

#include <bits/stdc++.h>
#define ld long double
#define ll long long int
#define IOS ios::sync_with_stdio(0),cout.tie(0)
#define pii pair<int,int>
#define ff first
#define ss second
using namespace std;
char table[10][10];
int n = 3;
//H->健康、Q->隔離、X->確診
fstream f;

void init(){
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= n;j++){
            table[i][j] = 'H';
        }
    }
}

bool check(){
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= n;j++){
            if(table[i][j] == 'H')return 0;
        }
    }
    return 1;
}

int get_pos(int s){
    int t = 0;
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= n;j++){
            if(s % 2){table[i][j] = 'X';t++;}
            s = s >> 1;
        }
    }
    return t;
}

void print(int s){
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= n;j++){
            f<<table[i][j]<<" ";
        }
        f<<endl;
    }
    f << s <<endl<<endl;
}

void setup(pii pos){
    bool f = 0;
    if(table[pos.ff][pos.ss] == 'X')return;
    for(int i = max(pos.ff-1,1);i <= min(pos.ff+1,n);i++){
        for(int j = max(pos.ss-1,1);j <= min(pos.ss+1,n);j++){
            if(table[i][j] == 'X'){f = 1;break;}
        }
    }
    if(f == 1)table[pos.ff][pos.ss] = 'Q';
    return;
}

ld C(int np,int mp){
    ld ans = 1;
    int t = min(mp,np-mp);
    for(int i = np;i > np-t;i--)ans *= i;
    for(int i = 1;i <= t;i++)ans /= i;
    return ans;
}

int main(){
    IOS;
    init();
    f.open("/Users/wupeien/Desktop/高二下學期資料夾/九宮格機率/6pos.txt",ios::out|ios::trunc);
    int s = 0,total = 0;
    ll m = pow(2,n*n);
    cout<<m<<endl;
    int test[40];fill(test,test+40,0);
    //s->狀態壓縮，m->總共次數2^36
    for(int i = 0;i < m;i++){
        init();
        int t = get_pos(s);
        for(int i = 1;i <= n;i++){
            for(int j = 1;j <= n;j++){
                setup({i,j});
            }
        }
        if(check()){test[t]++;total++;}
        print(s);
        if(i % 10000 == 0)cout<<"Progress: "<<(ld)100*i/m<<"%"<<endl;
        s++;
    }
    ld p = 0.0;
    for(int i = 1;i <= (n*n);i++)p += i * (ld)test[i];
    for(int i = 1;i <= (n*n);i++){
        cout<<i<<": "<<test[i]<<endl;
        cout<<C(n*n,i)<<endl<<endl;
    }
    p /= (ld)total;
    cout<<"全班隔離人數期望值："<<p<<endl;
    f << endl;
    for(int i = 1;i <= (n*n);i++){f << test[i]<<" ";}
    f << endl;
    for(int i = 1;i <= (n*n);i++){f << C(n*n,i)<<" ";}
    f << endl;
    f << p << endl;
    for(int i = 1;i <= (n*n);i++){
        cout<<test[i]<<" ";
    }
    cout<<endl;
    
}