#include <assert.h>
#include <stdlib.h>
#include "mm_help.h"

void bw (char * g1, char * g2, int * b, int * w)
{
	int i, c1[20], c2[20];
	(*b) = 0; (*w) = 0;
	for (i=0; i<20; ++i) {
		c1[i] = c2[i] = 0;
	}
	for (i=0; g1[i]; ++i) {
		assert (g2[i]);
		if (g1[i] == g2[i]) {
			(*b)++;
		} else {
			c1[(int)(g1[i]-'A')]++;
			c2[(int)(g2[i]-'A')]++;
		}
	}
	assert (!g2[i]);
	for (i=0; i<20; ++i) {
		if (c1[i] < c2[i])
			(*w) += c1[i];
		else
			(*w) += c2[i];
	}
}

struct guess * get_guesses (int col, int len, int unique)
{
	struct guess * ret, * last;
	int used[20];
	int pos = 1;
	int i, j, m;
	assert (col < 20 && len < 20);
	ret = last = NULL;
	if (!unique) {
		for (i=1; i<=len; ++i) {
			pos *= col;
			if (pos > 1100000)
				return NULL;
		}
		ret = last = NULL;
		for (i=0; i<pos; ++i) {
			struct guess * g = malloc (sizeof (struct guess));
			int val, j;
			g->next = NULL;
			g->g[len] = 0;
			val = i;
			for (j=len-1; j>= 0; j--) {
				g->g[j] = 'A' + val%col;
				val /= col;
			}
			if (!last) {
				ret = last = g;
			} else {
				last->next = g;
				last = g;
			}
		}
		return ret;
	}
	/* UNIQUE */
	assert (col >= len);
	pos = 1;
	m = col;
	for (i=0; i<len; ++i,--m) {
		pos *= m;
		if (pos > 1100000)
			return NULL;
	}
	ret = malloc (sizeof (struct guess));
	last = ret;
	ret->next = NULL;
	for (i=0; i<col; ++i) {
		used[i] = 0;
	}
	for (i=0; i<len; ++i) {
		ret->g[i] = 'A' + i;
		used[i] = 1;
	}
	while (1) {
		int max = -1;
		struct guess * gn;
		gn = malloc (sizeof (struct guess));
		for (i=0; i<len; ++i) {
			gn->g[i] = last->g[i];
		}
		gn->next = NULL;
		i = col-1;
		while (max < 0 && i >= 0) {
			if (!used[i]) {
				max = i;
				break;
			}
			i--;
		}
		i = len-1;
		while (i>= 0 && gn->g[i]-'A' >= max) {
			assert (used[gn->g[i]-'A']);
			used[gn->g[i]-'A'] = 0;
			max = gn->g[i]-'A';
			i--;
		}
		if (i < 0) {
			free (gn);
			break;
		}
		assert (max >gn->g[i]-'A');
		assert (used[gn->g[i]-'A']);
		used[gn->g[i]-'A'] = 0;
		gn->g[i]++;
		while (used[gn->g[i]-'A'])
			gn->g[i]++;
		used[gn->g[i]-'A'] = 1;
		j=0;
		for (i++; i<len; ++i) {
			while (used[j])
				j++;
			gn->g[i] = 'A'+j;
			used[j] = 1;
		}
		last->next = gn;
		last = gn;
	}
	return ret;
}