Here is my own testing program ...
Now tell me please what is wrong here???
N ==0 Q == 10
N ==1 Q == 1
N ==2 Q == 2
N ==3 Q == 3
N ==4 Q == 4
N ==5 Q == 5
N ==6 Q == 6
N ==7 Q == 7
N ==8 Q == 8
N ==9 Q == 9
N ==10 Q == 25
N == 11 -1
N ==12 Q == 26
N == 13 -1
N ==14 Q == 27
N ==15 Q == 35
N ==16 Q == 28
N == 17 -1
N ==18 Q == 29
N == 19 -1
N ==20 Q == 45
N ==21 Q == 37
N == 22 -1
N == 23 -1
N ==24 Q == 38
N ==25 Q == 55
N == 26 -1
N ==27 Q == 39
N ==28 Q == 47
N == 29 -1
N ==30 Q == 56
N == 31 -1
N ==32 Q == 48
N == 33 -1
N == 34 -1
N ==35 Q == 57
N ==36 Q == 49
N == 37 -1
N == 38 -1
N == 39 -1
N ==40 Q == 58
N == 41 -1
N ==42 Q == 67
N == 43 -1
N == 44 -1
N ==45 Q == 59
N == 46 -1
N == 47 -1
N ==48 Q == 68
N ==49 Q == 77
N ==50 Q == 255
N == 51 -1
N == 52 -1
N == 53 -1
N ==54 Q == 69
N == 55 -1
N ==56 Q == 78
N == 57 -1
N == 58 -1
N == 59 -1
N ==60 Q == 256
N == 61 -1
N == 62 -1
N ==63 Q == 79
N ==64 Q == 88
N == 65 -1
N == 66 -1
N == 67 -1
N == 68 -1
N == 69 -1
N ==70 Q == 257
N == 71 -1
N ==72 Q == 89
N == 73 -1
N == 74 -1
N ==75 Q == 355
N == 76 -1
N == 77 -1
N == 78 -1
N == 79 -1
N ==80 Q == 258
N ==81 Q == 99
N == 82 -1
N == 83 -1
N ==84 Q == 267
N == 85 -1
N == 86 -1
N == 87 -1
N == 88 -1
N == 89 -1
N ==90 Q == 259
N == 91 -1
N == 92 -1
N == 93 -1
N == 94 -1
N == 95 -1
N ==96 Q == 268
N == 97 -1
N ==98 Q == 277
N == 99 -1
N ==100 Q == 455
N == 101 -1
N == 102 -1
N == 103 -1
N == 104 -1
N ==105 Q == 357
N == 106 -1
N == 107 -1
N ==108 Q == 269

this program fails (WA) at test 8

this program shouldn't fail...

Edited by author 23.11.2010 22:39
#include<iostream>

int main()
{

    int a, b;
    bool t = true;
    std::cin >> a;
        if(a < 0 || a > 109){
            std::cin >> a;
        }
            int k = 6, j = 9, i = 9, test = 4;
            while(test >= 1){
                k = 5;
                 while(k >= 1){
                     i = 9;
                     while(i >= 2){
                         j = 9;
                          while(j >= 2){
                              if(test != 1){
                                  if(test * j * i * k == a){
                                      b = (test*1000) + (k*100) + (i * 10) + (j);
                                      t = false;
                                  }
                             }else if(k != 1 && test == 1){
                                  if(j * i * k == a){
                                      b = (k*100) + (i * 10) + (j);
                                      t = false;
                                  }
                              }else if(k == 1 && test == 1){
                                  if(j * i  == a){
                                      b = (i*10) + j;
                                      //std::cout <<"i == "<<(i)<< " + j == " << j << '\n';
                                      t = false;
                                  }
                              }
                              j--;
                          }
                         i--;
                     }
                     k--;
                }test--;
            }
            if(a < 10){
                if(a==0){
                    b = 10;
                    t = false;
                }else if(a>=1){
                        b = a;
                        t = false;
                }
            }

        if(t == false){
            std::cout << b << '\n';
        }else{
            std::cout << -1 << '\n';
        }
    return 0;
}

Edited by author 23.11.2010 23:07

In fact i don't really know C but i had the same problem on test 8 and the reason was that i needed bigger in (in pascal int64).
Thanks.

try test 244140625

its answer is 555555555555

I think the limit is 0<= N <= (10^9) not 109