// game2: a player gives or receives 1 unit, energy is number of units the
// player has, using Metropolis acceptance
// CO904, Ellak Somfai

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define MIN(x,y)    ((x)<(y) ? (x) : (y))


int main(int argc, char **argv) {
	int a;
        int i, j;
	double T;
	int mc_per_sample, n_samples;

	// read command line arguments
        if (argc == 4) {
                sscanf(argv[1], "%lf", &T);
                sscanf(argv[2], "%d",  &mc_per_sample);
                sscanf(argv[3], "%d", &n_samples);
        } else {
                printf("Usage:  game2  <T> <mc_per_sample>  <n_samples>\n");
                exit(1);
        }

	// initialise random number generator
        srand48(1231230);

	// initialise state
	a = 10;
	// loop on samples
        for (i = 0; i < n_samples; i++) {
		// loop on monte-carlo steps
		for (j = 0; j < mc_per_sample; j++) {
			int change;
			double e_old, e_new;
			double boltzmann;

			// change: +1 or -1
			change = 2* ((int)(drand48() * 2)) - 1;
			if (a+change < 0) {
				// target is invalid: reject
				continue;
			}

			e_old = a;
			e_new = a + change;
			boltzmann = exp(-(e_new - e_old) / T);
			if (drand48() < MIN(boltzmann, 1.)) {
				// accept
				a = a + change;
			}

		}
		printf("%d\n", a);
        }

	return 0;
}