simulate_good.cpp

#include <stdlib.h>
#include <time.h>
#include "iostream"
#include <math.h>
using namespace std;
double p;
int interval(double l, double a){

	a = a - floor(a);
	if(l<1.0) return 0;

	double t = ((double) rand())/((double) RAND_MAX);
	
	if(t>p || l-a<1.0){
		t = ((double) rand())/((double) RAND_MAX)*(l-1.0);
		return interval(t,a) + interval(l-t-1.0,a-t) + 1;
	}else{
		t = floor(((double) rand())/((double) RAND_MAX)*floor(l-1.0-a));
		return interval(t+a,a) + interval(l-a-t-1,0) + 1;
	}
}

int main(int argc, char* argv[]) { 
	srand(time(NULL));
	double l = atof(argv[1]);
	p = atof(argv[2]);
	int itr = atoi(argv[3]);
	long t=0;
	for(int i=0;i<itr;i++){
		t+= interval(l,0);
	}
	cout << ((double) t )/ ((double) itr )/ l << endl;
	return 0;
}