/* look for ways to break the cryptographic hash */

#define LEN 1000

static int iii;
static int jjj;
static int kkk;
static int lll;
static int mmm;

#define OFF1 (iii)
#define OFF2 (OFF1+jjj)
#define OFF3 (OFF2+kkk)
#define OFF4 (OFF3+lll)
#define GAP  3    /* how many permutations per gap */
#define VAR  4    /* how many uses of each block */

#define LIMIT 30  /* we need at least 30 permutations */
#define MAX 50    /* examine deltas up to 50 blocks apart */

int check(int x[LEN][VAR], int *a, int len) {
  int i;
  int on = LIMIT;
  int off = 0;
  int limit = LIMIT;
  for (i=0; i<=GAP*(a[len-1]+OFF3+5); ++i) {
    int temp;
    int count = 0;
    int j, k;
    ++on;
    temp = (off < on) ? off : on;
    if (temp >= limit) return 0;
    for (j=0; j<VAR; ++j) {
      for (k=0; k<len; ++k) {
	if (x[i][j] == a[k]) {
	  ++count;
	}
      }
    }
    if (count == 1) {
      off = on;   /* we can only turn off if we were on */
      on = temp;  /* we're allowed to stay on either way */
    } else if (count > 1) {
      int temp = (off < on) ? off : on;
      off = temp; /* we can choose either way */
      on = temp;  /* we can choose either way */
    }
  }
  if (off < limit) {
    if (len > 5) {
      printf("found a bad one  %d %d\n  ", off, on);
      for (i=0; i<len; ++i) {
	printf("%d ", a[i]);
      }
      printf(":\n");
    }
    return 1;
  }
  return 0;
}

#define CYCLE (GAP*4)

int maine()
{
  int a[20];
  int x[LEN][VAR];
  int i,j;

  /* explain how the blocks are distributed */
  for (i=0; i<LEN; ++i) {
    for (j=0; j<VAR; ++j) {
      x[i][j] = -1;
    }
  }
  for (i=0; i<LEN/GAP-OFF3; ++i) {
    int offset;
    int base;

    base = offset = GAP*i+2;
    if (x[offset][0] != -1) return 1;
    x[offset][0] = i;

    offset = GAP*(i + OFF1) - GAP*6*(i%4);
    if (offset < base) return 1;
    if (x[offset][1] != -1) return 1;
    x[offset][1] = i;

    offset = GAP*(i + OFF2) - GAP*6*((i+2)%4);
    if (offset < base) return 1;
    if (x[offset][2] != -1) return 1;
    x[offset][2] = i;

    offset = GAP*(i + OFF3);
    if (offset < base) return 1;
    if (x[offset][3] != -1) return 1;
    x[offset][3] = i;

#ifdef NEVER
    offset = i+OFF4 - 6*((i+3)%4);
    if (x[offset][4] != -1) return 1;
    x[offset][4] = i;
#endif
  }

  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    if (check(x, a, 1)) return 1;
  }

  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      if (check(x, a, 2)) return 1;
    }
  }

  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	if (check(x, a, 3)) return 1;
      }
    }
  }

  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  if (check(x, a, 4)) return 1;
	}
      }
    }
  }

  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    if (check(x, a, 5)) return 1;
	  }
	}
      }
    }
  }

  printf("six %d: %d %d %d  %d %d\n", OFF3, iii, jjj, kkk, lll, mmm);
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      if (check(x, a, 6)) return 1;
	    }
	  }
	}
      }
    }
  }

  printf("seven:\n");
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      for (a[6]=a[5]+1; a[6]<MAX; ++a[6]) {
		if (check(x, a, 7)) return 1;
	      }
	    }
	  }
	}
      }
    }
  }

  printf("eight:\n");
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      for (a[6]=a[5]+1; a[6]<MAX; ++a[6]) {
		for (a[7]=a[6]+1; a[7]<MAX; ++a[7]) {
		  if (check(x, a, 8)) return 1;
		}
	      }
	    }
	  }
	}
      }
    }
  }

  printf("nine:\n");
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      for (a[6]=a[5]+1; a[6]<MAX; ++a[6]) {
		for (a[7]=a[6]+1; a[7]<MAX; ++a[7]) {
		  for (a[8]=a[7]+1; a[8]<MAX; ++a[8]) {
		    if (check(x, a, 9)) return 1;
		  }
		}
	      }
	    }
	  }
	}
      }
    }
  }

  printf("ten:\n");
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      for (a[6]=a[5]+1; a[6]<MAX; ++a[6]) {
		for (a[7]=a[6]+1; a[7]<MAX; ++a[7]) {
		  for (a[8]=a[7]+1; a[8]<MAX; ++a[8]) {
		    for (a[9]=a[8]+1; a[9]<MAX; ++a[9]) {
		      if (check(x, a, 10)) return 1;
		    }
		  }
		}
	      }
	    }
	  }
	}
      }
    }
  }

  printf("eleven:\n");
  for (a[0]=0; a[0]<CYCLE; ++a[0]) {
    for (a[1]=a[0]+1; a[1]<MAX; ++a[1]) {
      for (a[2]=a[1]+1; a[2]<MAX; ++a[2]) {
	for (a[3]=a[2]+1; a[3]<MAX; ++a[3]) {
	  for (a[4]=a[3]+1; a[4]<MAX; ++a[4]) {
	    for (a[5]=a[4]+1; a[5]<MAX; ++a[5]) {
	      for (a[6]=a[5]+1; a[6]<MAX; ++a[6]) {
		for (a[7]=a[6]+1; a[7]<MAX; ++a[7]) {
		  for (a[8]=a[7]+1; a[8]<MAX; ++a[8]) {
		    for (a[9]=a[8]+1; a[9]<MAX; ++a[9]) {
		      for (a[10]=a[9]+1; a[10]<MAX; ++a[10]) {
			if (check(x, a, 11)) return 1;
		      }
		    }
		  }
		}
	      }
	    }
	  }
	}
      }
    }
  }
  return 0;
}

int main()
{
  int i;
  for (i=46; i<50; ++i) {
    for (iii=1; iii<i; iii+=1) {
      for (jjj=1; jjj<i-iii; jjj+=1) {
	kkk = i-iii-jjj;
	for (lll=6*GAP; lll<=6*GAP; ++lll) {
	  for (mmm=6*GAP; mmm<=6*GAP; ++mmm) {
	    maine();
	  }
	}
      }
    }
  }
}