//cow00.c   -- by tsaiwn@csie.nctu.edu.tw
//#define DEBUG
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#include <sys/types.h>
#include <sys/time.h>
int possible[5040];    // global variable
int npsible;    // global variable 記著有幾個可能答案 //
int reduceAnswers(int myGuess, int nbull, int ncow);
int readLine(char*);
void checkAnswer(int xx, int yy, int *na, int *nb, int item);
int main(){
       int n, tmp, nguess, nbull, ncow;
       int yn, myGuess;
       long now= time(0);
       srand( now &0xffff);    /* randomize, see "man srand" */
  again:
       npsible = prepare_all_possible_answer();   // 放在 possible[5040]
       nbull = ncow = nguess = 0;
       while(nbull != 4) {
#ifdef DEBUG
         fprintf(stderr, "DEBUG: npsible = %d\n", npsible);
#endif
          // 由所有可能答案中隨便挑一個當 myGuess, 並印出說猜該數 //
           n = rand() % npsible;   /* 0.. npsible -1 */
           tmp = possible[0]; possible[0] = possible[n]; possible[n] = tmp;
           myGuess = possible[0];   /* 永遠猜第 0 個比較好寫 */
           fprintf(stderr, "I guess your number"
                           " is %4.4d, 幾A 幾B? ", myGuess);
           ++nguess;  // 猜的次數
          // 由 user 取得幾A放 nbull, 幾 B 放 ncow
           getAnswer(&nbull, &ncow);
           if(nbull == 4){
               if(nguess<5)fprintf(stderr, "才 %d 次", nguess);
               fprintf(stderr, "喔 Yeah 我猜到了!\n");
               if(nguess>6)fprintf(stderr, "這麼衰..猜了 %d 次!\n", nguess);
               break;
           }
           /* 還沒猜對, 把不可能的答案刪除並修正 npsible */
           npsible = reduceAnswers(myGuess, nbull, ncow);
           if(npsible <= 0){
               fprintf(stderr, "You 欺騙我!\n");
               break;
           }
       }
       fprintf(stderr, "\n要不要繼續玩下一攤(yes, no)? ");
       yn = askPlayAgain();
       if(yn) goto again;
       fprintf(stderr, "Thank you and Bye!\n");
}
//function to check if the user want to play again
int
askPlayAgain(){    /* return 1 if he/she said YES */
    static char tmp[99];
    readLine(tmp);
    if(tmp[0] == 'Y' || *tmp == 'y') return 1;
    if(toupper(tmp[0]) == 'N') return 0;
    fprintf(stderr, "Please type N or Y: ");
    return askPlayAgain();    /* recursively call myself */
}
// function to get how many A + how many B from player
int
getAnswer(int *nbull, int *ncow){
    static char tmp[99], i;
    char *pa, *pb;    /* used to make the program more intelegent */
    readLine(tmp);
    pa = strchr(tmp, 'A'); if(pa==0) pa=strchr(tmp, 'a');
    pb = strchr(tmp, 'B'); if(pb==0) pb=strchr(tmp, 'b');
    if(pa==0 && pb!=0) pa = pb+3;
    if(pb==0 && pa!=0) pb = pa+3;
    for(i=0; i< strlen(tmp); i++){
       if(tmp[i] == 'A' || tmp[i] == 'a') tmp[i] = ' ';
       if(tmp[i] == 'B' || tmp[i] == 'b') tmp[i] = ' ';
       if(tmp[i] == ',' || tmp[i] == ';') tmp[i] = ' ';
    }
    *nbull = *ncow = 0;  
    sscanf(tmp, "%d %d", nbull, ncow);   /* 注意 nbull, ncow */
    if(pa>pb) { i = *nbull; *nbull = *ncow; *ncow = i; } /*swap A, B*/
#ifdef DEBUG
     fprintf(stderr, "===%d A, %d B\n", *nbull, *ncow);
#endif
    return *nbull;
}
/// function   prepare_all_possible_answer();
int
prepare_all_possible_answer(){
      //想辦法 (用四層 for loop ) 把所有可能答案 放在 possible[5040]
      //共有 5040 個, 最小 0123, 最大 9876
      //(因每位不能重複)
    int * x = possible;    /* 之後 x[0] 就是 possible[0] */
    // 以下是原來給大家的例子
    int p=0, i,k,m,n;
    for(i=0; i<=9; i++){
        for(k=0; k<=9; k++){
            if(k==i) continue;   /* 第二位k與第一位數i相同的都不要 */
            for(m=0; m<=9; m++){
                if(m==k || m==i) continue;
                for(n=0; n<=9; n++){
                   if(n==m || n==k || n==i) continue;
                   x[p++] = i*1000+k*100+m*10+n;
                }
            }
        }
    }
    return p;
}
/// function reduceAnswers()
int
reduceAnswers(int myGuess, int nbull, int ncow){
       // 刪除不可能之答案, 並將可能之答案放在 array 前端 //
       // 以下只做刪除不可能之答案 //
       /// 順便把可能答案往 array 前端移 : 留給大家想 ..
       int na, nb, i;
       int n= 0;  /* possible[0] 是第一個可以蓋掉的 */
             /* 所以由 possible[1] 開始看看有哪些是有可能的就留下來 */
       for(i=1; i< npsible; i++){
             //叫用以前的 checkAnswer(要稍微修正) 比較 myGuess 和 possible[i]
             //以便知道myGuess對於 possible[i]是幾A幾B //
             //若幾A幾B剛好與 nbull 和 ncow 完全相同表示為可能答案 //
             //否則都要消去 //
#ifdef DEBUG
    if(i==1 || i==npsible-1 || i%100 == 0)
       fprintf(stderr, "DEBUG: %4d) ", i);
#endif
            checkAnswer(myGuess, possible[i], &na, &nb, i);
            if(na == nbull && nb==ncow){
                possible[n] = possible[i];    /*可能的答案移到 array 較前面*/
                ++n;   /* n 指向下一個可蓋掉的元素 possible[n] */
            }
       }
       npsible = n;
       return n;
}
int readLine(char* p) {
    int n=0;
    fgets(p, 88, stdin);
    while( (p[n] != '\n') && (p[n] != 0) ) ++n;
    return n;  // 共讀到 n 個 char
}
void checkAnswer(int xx, int yy, int *na, int *nb, int item) {
    fprintf(stderr, "Not implemented yet !!!\n");
}
/***
/// 要稍微修正checkAnswer
    因以前是比兩個 array
    現在是比兩個整數, 要先用 %10 的方法拆成四位數 //
*************************************************/