ae1b (tables) wa

[savados]

Hi. I'm trying to learn C, so my code is very-very ugly, but I don't understand why do I get WA. I solved this problem with Python using the same algorythm, but in C I get WA on some testcase ( somewhere > 14). My solution works fine with '1 1 1\n1', it returns 1.

acc

[leppyr64]

int x,y;
scanf("%d %d",&x,&y);

Use scanf for reading input. Endofline character is not always "\n", it might be "\r\n" depending on who create the file. In fact since SPOJ uses multiple input files to test problems multiple files might be created in two different sources and have different endofline types. scanf doesn't care what type of EOL it is. Scanf will cross lines as well the code listed above will successfully read "1\n1\n"

[savados]

Thanks, you know about scanf, but how can I read the second line: n1 n2 n3 ... nn? I tried scanf("%s", line2), but it reads only n1, as documented.

[leppyr64]

int n,x[100]; // assuming n <= 100
for(int i=0;i<n;i++)
    scanf("%d",&n[i]);

[savados]

Thanks, leppy! And the code isn't so ugly now.

[eeexort]

Hi my code is running fine on ideone and my pc with simple cases. But for some reason i am getting WA. Any help appreciated..

#include<stdio.h>
#include<conio.h>
int main()
{
    int i,n,k,h,j,temp,nails,count,sum=0;
    scanf("%d%d%d",&n,&k,&h);
    int s[n];  
    for(i=0;i<n;i++)
    {
       scanf("%d",&s[i]);
    }
    for(i=0;i<(n-1);i++)
    {for(j=0;j<=(n-i-1);j++)
       {
          if(s[j]>s[j+1])
          {
             temp=s[j];
             s[j]=s[j+1];
             s[j+1]=temp;
             }
       }
     }
     nails=k*h;
     i=n-1;
     while(sum<nails&&i>=0)
     {
       sum+=s[i];
       i--;
     }
     printf("%d",n-1-i);
     getch();
     return 0;
     }

[leppyr64]

Check your sorting algorithm.

[eeexort]

I edited my sorting algo...and it is running fine on my pc but giving wrong answer on ideone.com. How is this possible? Same code different answers on different compilers?

[leppyr64]

Your sorting algorithm is still not accurate. Your edit only made it more inefficient. What's the value of s[n]?

[eeexort]

I think the value of s[n] will be the number of nails in the last box? or is it '\0' which i really doubt...and i changed my sorting yet again is this getting me closer? or am i far from the logic ?

[leppyr64]

You have n boxes of nails and you think they are in 0..n?

[eeexort]

Sorry sir I do not understand. s[n] will contain the number of nails in the last box given by the user. They are not in ascending order or anything. That is why i sort the array and then add the sum till it is more than no. of nails needed. Probably i m doing some C language grammatical error.

[leppyr64]

    for(i=0;i<n;i++)
    {
       scanf("%d",&s[i]);

In this segment of code you read all of the boxes into s. i was never equal to n during this loop.

My question again is, "What value is at s[n]?" The correct answer to this question is, "I do not know." Now knowing that you should only be looking at indexes 0 to n-1, examine your sorting algorithm carefully.

Also, do not worry about not understanding. I'm trying to help you do the thinking so that you can learn more easily later