Dog-flea.cpp

#include <cstdio>
#include<random>
#include<cmath>
constexpr int gen_n=210;
constexpr int init_a=20;
constexpr int init_b=0;

int main() {

    int dog_a=init_a,dog_b=init_b;


    for (int i = 0; i < gen_n; ++i) {

        std::random_device rd;
        std::default_random_engine engine(rd());
        std::uniform_int_distribution<int> dist(1,gen_n+1);


        double pro_a=(double)std::abs(dog_a-dist(engine))/(double)gen_n;
        double pro_b=(double)std::abs(dog_b-dist(engine))/(double)gen_n;

         if(pro_a>pro_b&&dog_b>0){
             dog_a++;
             dog_b--;
         }else if(pro_a<pro_b&&dog_a>0){
             dog_a--;
             dog_b++;
         }


        if(dog_a==init_a&&dog_b==init_b){
            std::printf("Initial State number of generations:%d",i);
            break;
        }


       std::printf("x(%d)=(%d,%d)\n",i,dog_a,dog_b);

    }

    return 0;
}