/*    Copyright (C) 1998-2003 XIAO, Gang of Universite de Nice - Sophia Antipolis
 
 *
 
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 
 */
 
 
 
 /* Solves cryptarithms, to be interfaced by wims. */
 
 
 
#define MAX_LINES 64
 
#define MAX_CHARS 32
 
 
 
#include "../includes.h"
 
 
 
char basetab[MAX_LINES][MAX_CHARS];
 
int carry[MAX_LINES][MAX_CHARS+8];
 
char corresp[32],bcorresp[16];
 
int linecnt,charcnt[MAX_LINES],activelen,maxlen;
 
int active[MAX_LINES];
 
int style[MAX_LINES];
 
int total=0;
 
 
 
char *input;
 
 
 
/* Print the result */
 
void printresult(char curr[])
 
{
 
  int i,j;
 
  char ch;
 
  for(i=0;i<linecnt;i++) {
 
    for(j=0;j<charcnt[i];j++) {
 
      ch=basetab[i][j];
 
      if(ch==0) ch=' ';
 
      else if(ch>='A' && ch<='Z') ch=curr[ch-'A'];
 
    }
 
  }
 
}
 
 
 
/* returns 1 if OK, 0 if bad. */
 
int putvalue(char ch, char k, char curr[], char currb[])
 
{
 
  int i=ch-'A';
 
  if(ch==0) {
 
    if(k>0) return 0; else return 1;
 
  }
 
  if((curr[i]!=-1 && curr[i]!=k) || (currb[k]!=0 && currb[k]!=ch))
 
    return 0;
 
  curr[i]=k;currb[k]=ch; return 1;
 
}
 
 
 
/* check that leading number is not 0. Returns 0 if bad. */
 
int checklead(char curr[])
 
{
 
  int i;
 
  char ch;
 
  for(i=0;i<linecnt;i++) {
 
    ch=basetab[i][charcnt[i]-1];
 
    if(curr[ch-'A']<=0) return 0;
 
  }
 
  return 1;
 
}
 
 
 
/* returns 0 if fail, 1 if OK. */
 
int colcompute(int c,char curr[],char currb[])
 
{
 
  int i,j,k,sum;
 
  char ch;
 
 
 
  switch(style[1]) {
 
    case '-':
 
    case '+':
 
    case '.': {
 
      for(j=sum=0;j<linecnt;j++) {
 
        if(!active[j]) continue;
 
        ch=basetab[j][c];
 
        if(ch!=0) {
 
          if(style[j]!='-') sum+=curr[ch-'A'];
 
          else sum-=curr[ch-'A'];
 
        }
 
      }
 
      lastline:
 
      sum+=carry[linecnt-1][c];
 
      carry[linecnt-1][c+1]=(sum+10000)/10-1000; k=(sum+10000)%10;
 
      return putvalue(basetab[linecnt-1][c],k,curr,currb);
 
    }
 
 
 
    case '*': {
 
      char c1,c2;
 
      c2=basetab[0][c];
 
      if(c2!=0) c2=curr[c2-'A'];
 
      for(i=0;i<c && i<linecnt-3;i++) {
 
        c1=basetab[1][i];
 
        if(c2*c1!=0) sum=c2*curr[c1-'A']+carry[2+i][c];
 
        else sum=carry[2+i][c];
 
        carry[2+i][c+1]=sum/10;
 
        if(!putvalue(basetab[2+i][c],sum%10,curr,currb))
 
          return 0;
 
      }
 
      c2=basetab[1][c];
 
      if(c2!=0) {
 
        c2=curr[c2-'A'];
 
        for(i=0;i<=c;i++) {
 
          c1=basetab[0][i];
 
          if(c1==0) break;
 
          sum=c2*curr[c1-'A']+carry[2+c][i];
 
          carry[2+c][i+1]=sum/10;
 
          if(!putvalue(basetab[2+c][i],sum%10,curr,currb))
 
            return 0;
 
        }
 
      }
 
      for(i=sum=0;i<=c && i<linecnt-3;i++) {
 
          ch=basetab[2+i][c-i];
 
          if(ch!=0) sum+=curr[ch-'A'];
 
      }
 
      goto lastline;
 
    }
 
 
 
/* short multiplication */
 
    case '$': {
 
      char c1,c2;
 
      for(j=sum=0;j<=c;j++) {
 
        c1=basetab[0][j]; c2=basetab[1][c-j];
 
        if(c1==0) break;
 
        if(c2==0) continue;
 
        sum+=curr[c1-'A']*curr[c2-'A'];
 
      }
 
      goto lastline;
 
    }
 
 
 
    default: return 0;
 
  }
 
}
 
 
 
void column(int c, char prev[], char prevb[])
 
{
 
  char curr[32], currb[16];
 
  int lreg[MAX_LINES],lfix[MAX_LINES];
 
  int i,j,icarry;
 
  char ch;
 
 
 
 
 
  for(i=0;i<linecnt;i++) {
 
    if(!active[i]) continue;
 
    ch=basetab[i][c];
 
    if(ch==0 || prev[ch-'A']!=-1) lfix[i]=1;
 
  }
 
  for(icarry=0;;icarry=1) {
 
    memmove(currb
,prevb
,sizeof(currb
));  
    for(i=0;i<linecnt;i++) {
 
      if(!active[i] || lfix[i]) continue;
 
      for(j=lreg[i]+icarry;j<10 && prevb[j]!=0;j++);
 
      if(j>=10) {
 
        for(j=0;j<10 && prevb[j]!=0;j++);
 
        if(j>=10) return;
 
        icarry=1;
 
      }
 
      else icarry=0;
 
      lreg[i]=j;
 
    }
 
    if(icarry) break;
 
    for(i=0;i<linecnt;i++) {
 
      if(!active[i] || lfix[i]) continue;
 
      if(!putvalue(basetab[i][c],lreg[i],curr,currb)) goto loopend;
 
    }
 
    if(!colcompute(c,curr,currb)) continue;
 
    if(c<activelen-1) column(c+1,curr,currb);
 
    else {
 
      for(i=activelen;i<maxlen;i++) {
 
        if(!colcompute(i,curr,currb)) goto loopend;
 
      }
 
      for(i=0;i<linecnt;i++) {
 
        if(active[i]) continue;
 
        if(carry[i][maxlen]) goto loopend;
 
      }
 
      if(!checklead(curr)) goto loopend;
 
      total++;
 
      printresult(curr);
 
    }
 
    loopend:
 
  }
 
}
 
 
 
int main(int argc, char *argv[])
 
{
 
  char *p,*p2,*p3;
 
  int i;
 
  input
=getenv("wims_exec_parm"); 
/* nothing to do if no problem */
 
  if(input==NULL || *input==0) return 0;
 
 
 
  memset(basetab
,0,sizeof(basetab
));  
  memset(corresp
,-1,sizeof(corresp
));  
  memset(bcorresp
,0,sizeof(bcorresp
));  
  memset(carry
,0,sizeof(carry
));  
  memset(active
,0,sizeof(active
));  
 
 
  *p=0;
 
  activelen=maxlen=0;
 
  active[0]=active[1]=1;
 
  for(linecnt=0,p=input;*p!=0 && linecnt<MAX_LINES;p=p3) {
 
    if(p2==NULL) {
 
    }
 
    else p3=p2+1;
 
    if(strchr("+-*/=.",*p
)!=NULL
) {  
      style[linecnt]=*p;p++;
 
    }
 
    else style[linecnt]='+';
 
    if(*p3==0) style[linecnt]='=';
 
    if(linecnt>1) {
 
     switch(style[1]) {
 
       case '+':
 
       case '-': {
 
        if(*p3!=0) active[linecnt]=1;
 
        break;
 
       }
 
 
 
       case '*':
 
       case '/':
 
       case '=':
 
       break;
 
    }
 
  }
 
  while(p2
>p 
&& isspace(*(p2
-1))) p2
--;  
  if(p2>p+MAX_CHARS) p2=p+MAX_CHARS;
 
  *p2=0;
 
  if(p2<=p) continue;
 
  for(i=0;i<p2-p;i++) {
 
    char ch;
 
/* bad char */
 
    if(ch<'A' || ch>'Z') return 1;
 
      basetab[linecnt][i]=ch;
 
    }
 
    charcnt[linecnt]=p2-p;
 
    if(active[linecnt] && p2-p>activelen) activelen=p2-p;
 
    if(p2-p>maxlen) maxlen=p2-p;
 
    linecnt++;
 
  }
 
/* multiplication */
 
  if(style[1]=='*') {
 
    if(linecnt==3) style[1]='$';
 
    else {
 
      if(linecnt!=charcnt[1]+3) return 1;
 
    for(i=3;i<linecnt-1;i++)
 
      if(charcnt[i]+i-2>maxlen) maxlen=charcnt[i]+i-2;
 
    }
 
  }
 
 
 
  column(0,corresp,bcorresp);
 
  printf("\n!total %d solution(s).\n\n",total
);  
  return 0;
 
}