/* Le compte est bon - version dynamique
* Copyright (C) 2002 Lucas Nussbaum <lucas@lucas-nussbaum.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdlib.h>
#include <stdio.h>
typedef enum {ADD, MULT, SUB, DIV, EMPTY} operation;
typedef int boolean;
#define TRUE 1
#define FALSE 0
struct result {
unsigned int val; /* value */
operation op; /* operator */
struct result * l; /* left operand */
struct result * r; /* right operand */
unsigned short used; /* digits used */
struct result * next; /* you know what a linked list is, don't you ? */
};
const char dispops[4] = { '+', '*', '-', '/' };
/* initializes a result struct */
struct result * resinit()
{
struct result * p;
p
= (struct result
*)malloc(sizeof(struct result
));
p->l = NULL;
p->r = NULL;
p->next = NULL;
p->op = EMPTY;
p->used = 0;
return p;
}
/* display the result in a readable form. called recursively. */
void dispres(struct result * p)
{
if (p->op!=EMPTY)
{
dispres(p->l);
dispres(p->r);
printf("%u %c %u = %u\n", p
->l
->val
, dispops
[p
->op
],p
->r
->val
, p
->val
);
}
}
/* test if 2 operands are compatible */
boolean compatible (struct result *p, struct result *q, unsigned short *used)
{
if (p->used&q->used) return FALSE;
*used = p->used|q->used;
return TRUE;
}
/* operators */
unsigned int op_add(unsigned int a, unsigned int b)
{
if (!(a&&b)) return -1;
return a + b;
}
unsigned int op_mult(unsigned int a, unsigned int b)
{
if ((a==1)||(b==1)) return -1;
return a * b;
}
unsigned int op_sub(unsigned int a, unsigned int b)
{
if (!(a&&b)) return -1;
return a - b;
}
unsigned int op_div(unsigned int a, unsigned int b)
{
if ((!b)||(b==1)||(a%b)) return -1;
return a / b;
}
unsigned int (*ops_func[4]) (unsigned int, unsigned int) = { op_add, op_mult, op_sub, op_div };
const operation ops[4] = { ADD, MULT, SUB, DIV };
/* calculate the result with those 2 operands and the operator provided */
/* /!\ MUST HAVE p->val >= q->val */
struct result * add(struct result * p, struct result * q, int op)
{
unsigned int res = 0;
struct result *r;
if ((res = ops_func[op](p->val, q->val)) == -1)
return NULL;
r = resinit();
r->op = ops[op];
r->l = p;
r->r = q;
r->val = res;
return r;
}
struct result * best = NULL;
int min = 10000;
int goal;
/* tests if result is better */
void resultest(struct result * res)
{
if (res->val==goal)
{
dispres(res);
}
}
/* add all possible results using the p & q operands to the s list */
void addresults(struct result ***s, struct result *p, struct result *q)
{
unsigned short used;
int i;
struct result * r;
/* switch if needed */
if (p->val < q->val)
{
struct result *tmp;
tmp = p;
p = q;
q = tmp;
}
if (compatible(p,q,&used))
for (i=0; i<4; i++) /* for each operator */
if ((r = add(p,q,i)))
{
r->used = used;
**s = r;
*s = &(r->next);
resultest(r);
}
}
/* main routine */
int main(int argc, char * argv[])
{
struct result * results[6];
struct result *p, **s, *q = NULL;
int i;
int argp = 1;
if (argc!=8)
{
printf("There should be 7 arguments. goal, following by the 6 numbers"
"to use\n");
}
/* we read the goal */
goal
= atoi(argv
[argp
++]);
/* we read the 6 base numbers */
results[0] = resinit();
p = results[0];
q = results[0];
p
->val
= atoi(argv
[argp
++]);
p->used = 1;
for (i = 1; i < 6; i++)
{
p = resinit();
p
->val
= atoi(argv
[argp
++]);
p->used = 1 << i;
q->next = p;
q = p;
}
for (p = results[0]; p; p=p->next)
printf(". Goal : %d\n", goal
);
/* 0) results composed by 1 base number
* = res[0] */
for (p = results[0]; p->next; p=p->next)
resultest(p);
/* 1) results composed by 2 base numbers
* = res[0] X res[0] */
s = &(results[1]);
for (p = results[0]; p->next; p=p->next)
for (q = p->next; q; q=q->next)
addresults(&s, p, q);
/* 2) results composed by 3 base numbers
* = res[1] X res[0] */
s = &(results[2]);
for (p = results[1]; p; p=p->next)
for (q = results[0]; q; q=q->next)
addresults(&s, p, q);
/* 3) results composed by 4 base numbers
* = res[1] X res[1] + res[2] X res[0] */
s = &(results[3]);
for (p = results[1]; p->next; p=p->next)
for (q = p->next; q; q=q->next)
addresults(&s, p, q);
for (p = results[2]; p; p=p->next)
for (q = results[0]; q; q=q->next)
addresults(&s, p, q);
/* 4) results composed by 5 base numbers
* = res[2] X res[1] + res[3] X res[0] */
s = &(results[4]);
for (p = results[3]; p; p=p->next)
for (q = results[0]; q; q=q->next)
addresults(&s, p, q);
for (p = results[2]; p; p=p->next)
for (q = results[1]; q; q=q->next)
addresults(&s, p, q);
/* 5) results composed by 6 base numbers
* = res[2] X res[2] + res[3] X res[1] + res[4] X res[0] */
s = &(results[5]);
for (p = results[2]; p->next; p=p->next)
for (q = p->next; q; q=q->next)
addresults(&s, p, q);
for (p = results[3]; p; p=p->next)
for (q = results[1]; q; q=q->next)
addresults(&s, p, q);
for (p = results[4]; p; p=p->next)
for (q = results[0]; q; q=q->next)
addresults(&s, p, q);
/* results analysis */
/* here, find best result */
for (i=0; i<6; i++)
{
p = results[i];
while (p)
{
if (abs((int)p
->val
-goal
)<min
)
{
best = p;
min = p->val-goal;
}
p = p->next;
}
}
printf("NOTFOUND %d %d\n", best
->val
, min
);
dispres(best);
}