/*
 * golomb.c
 *
 *  Created on: 26/03/2016
 *      Author: pedro
 *
 *      http://www.csplib.org/Problems/prob006/
 *      https://github.com/MiniZinc/minizinc-benchmarks/tree/master/golomb
 *      https://www.cril.univ-artois.fr/~lecoutre/benchmarks.html#
 *
 *		Golomb Ruler problem:
 *      The Golomb Ruler problem is the task of putting n marks on a ruler of length m such that the
 *      distance between any two pairs of marks is distinct.
 */

#include "golomb.h"

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

#include "../config.h"
#include "../constraints/fake_all_different.h"
#include "../constraints/ge.h"
#include "../constraints/lt.h"
#include "../constraints/minimize.h"
#include "../constraints/var_eq_minus.h"
#include "../split.h"
#include "../variables.h"

/*
 * Solve the Golomb ruler problem with N marks
 */
void run_golomb(int* csp_dims) {
	int n = csp_dims[0];
	unsigned int* mark;
	unsigned int* differences;
	unsigned long result;
	int i, j, d;

	// ruler variables
	mark = malloc((unsigned int)n * sizeof(unsigned int));
	// vector with the ID of the variables constrained with all_diff
	differences = malloc((unsigned int)n * ((unsigned int)n - 1) / 2 * sizeof(unsigned int));

	// Create the Golomb ruler main variables and lt constraint
	mark[1] = v_new_range(1, (unsigned int)n * (unsigned int)n, true);
	for (i = 2; i < n; i++) {
		mark[i] = v_new_range(0, (unsigned int)n * (unsigned int)n, true);
	}

	// for optimization
	c_minimize(mark[n - 1]);

	for (i = 1; i < n - 1; i++) {
		c_lt(mark[i], mark[i + 1]);
	}

	// Create the triangle of differences variables and its c_var_eq_minus constraints
	j = 0;
	for (d = 1; d < n; d++) {
		differences[j++] = mark[d];

		for (i = d + 1; i < n; i++) {
			differences[j] = v_new_range(0, (unsigned int)n * (unsigned int)n, false);

			c_var_eq_minus(differences[j++], mark[i], mark[i - d]);
		}
	}

	mark[0] = v_new_val(0);

	c_fake_all_different(differences, (unsigned int)n * ((unsigned int)n - 1) / 2);

	// Symmetry breaking
	c_lt(differences[0], differences[n * (n - 1) / 2 - 1]);

	if (OPTIMIZING) {
			printf("Optimizing one solution for Golomb Ruler with %u marks.\n", n);
	} else if (FINDING_ONE_SOLUTION) {
		printf("\nFinding one solution for Golomb Ruler with %u marks.\n", n);
	} else {
		printf("\nCounting all the solutions for Golomb Ruler with %u marks.\n", n);
	}

	// Solve the CSP
	result = solve_CSP();

	if (OPTIMIZING && result == 1) {
		printf("Best solution:\n");
		vs_print_single_val(mark, (unsigned int)n, 0);
		printf("\n");
		v_print_cost(0);

	} else if (FINDING_ONE_SOLUTION && result == 1) {
		printf("Solution:\n");
		vs_print_single_val(mark, (unsigned int)n, 0);
		printf("\n");

	} else {
		printf("%lu solution(s) found\n", result);
	}

	free(differences);
	free(mark);
}