hidoicode.c

/* http://qiita.com/tag1216/items/25ff0f957340c54ae73c */

/*
  usage: ./a.out|sed -e "s/ //g"
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

char *template="1 2 3 4 5 6 7 8 9";

int gen_pattern(char *buf){
  static int state;
  if(state == pow(3,8)){
    return 0;
  }
  memcpy(buf, template, strlen(template)+1);
  int i, tmp;
  tmp = state;
  for(i = 0; i < 8; i++){
    switch(tmp % 3){
    case 0:
      buf[i*2 + 1] = ' ';
      break;
    case 1:
      buf[i*2 + 1] = '+';
      break;
    case 2:
      buf[i*2 + 1] = '-';
      break;
    }
    tmp = tmp / 3;
  }
  state++;
  return 1;
}

int sum(int *array, int count){
  int tmp = 0;
  int i;
  for(i = 0; i < count; i++){
    tmp += array[i];
  }
  return tmp;
}

#define PLUS 0
#define MINUS 1

int parse_pattern(char *pattern){
  int i;
  int nums[9];
  int sign = PLUS;
  int curidx = 0;
  for(i = 0; i < 9; i++){
    nums[i] = 0;
  }

  for(i=0; i < strlen(template)+1; i++){
    switch(pattern[i]){
      
    case '+':
      if(sign == MINUS) nums[curidx] *= -1;
      sign = PLUS;
      curidx++;
      break;
      
    case '-':
      if(sign == MINUS) nums[curidx] *= -1;
      sign = MINUS;
      curidx++;
      break;

    case '\0':
      if(sign == MINUS) nums[curidx] *= -1;
      curidx++;
      break;

    case ' ':
      nums[curidx] *= 10;
      break;
      
    default:
      nums[curidx] += (pattern[i] - '0');
    }
  }
  return sum(nums, 9);
}

int main(void){
  char *buf = malloc(strlen(template)+1);
  int i, rv;
  while(gen_pattern(buf)){
    rv = parse_pattern(buf);
    if(rv==100){
      printf("%s = %d\n", buf, rv);
    }
  }
  free(buf);
  return 0;
}