JULKA: Subtraction of BIGNUMBERS (100 digits) in c

general
, ,
1

I was trying to solve the problem JULKA given on SPOJ

in the code i have assumed

1.number is the total number of apples

2.more is how many more apples Klaudia has than Natalia.

3.x is the number of apples with Klaudia

4.y is the number of apples with natalia.

my code works for the inputs

10

2

3232

1233

giving the outputs

6

4

2232

999

but fails for the input

999

1

giving the output

500

49

it should have given 499 instead of 49. i am posting my code plz suggest me a correct algorithm for subtraction

#include<stdio.h>
#include<string.h>
int main()
{
char x[103],y[103],number[103],more[103];
int t=10,ln,lm,lx,i,j,carry,k,l;
while(t--)
{
    for(i=0;i<=102;i++)
    {x[i]='\0';y[i]='\0';}
    carry=0;
    scanf("%s",number);
    scanf("%s",more);
    ln=strlen(number);
    lm=strlen(more);
    //Adding 0 at the beginning to make length of more = lengthe of number
    while(lm!=0)
    {
        more[ln-1]=more[lm-1];
        ln--;
        lm--;
    }
    for(i=0;i<ln;i++)
        more[i]='0';
    ln=strlen(number);

    //Calculation of x
    for(i=ln-1;i>=0;i--)
    {
        k=carry + (int)number[i]+(int)more[i]-96;
        x[i]=(int)k%10+48;
        carry=k/10;
    }
    l=ln;
    if(carry!=0)
    {
        while(l!=0)
        {
            x[l]=x[l-1];
            l--;
        }
        x[0]=carry+48;
    }
    k=((int)x[0]-48)%2;
    for(i=1;i<ln;i++)
    {
        k=k*10;
        l=(int)x[i]-48 + k;
        x[i]=l/2 + 48;
        k=l%2;

    }
    x[0]=((int)x[0]-48)/2 + 48;
    ln=strlen(number);

    //PRINTING x
    i=0;
    while(x[i]=='0')i++;
    if(strlen(x)==i)
        printf("0");
    else
        for(l=i;l<=ln;l++)
            printf("%c",x[l]);
    printf("\n");

    //SUBTRACTION
    for(i=ln-1;i>=0;i--)
            {
                if(x[i]>=more[i])
                {
                    y[i]=(int)((int)x[i]-(int)more[i])+48;
                }
                else
                {
                    x[i-1]=(int)((int)x[i-1]-1);
                    l=(int)((int)x[i]+10-(int)more[i]);
                    y[i]=l+48;
                }
            }

    //PRINTING y
    i=0;
    while(y[i]=='0')i++;
    if(strlen(y)==i)
        printf("0");
    else
        for(l=i;l<=ln;l++)
            printf("%c",y[l]);
    printf("\n");
}
return 0;

}

2

The code you have written for subtraction is right. I took out that snippet and checked it separately. Check some other portion of your code. Since, the problem is in classical section in spoj. Giving away the exact error won’t be fun.

Here is the modified part of your code of only subtraction:

int main()
{
	char x[103],y[103],number[103],more[103];
	int t=10,ln,lm,lx,i,j,carry,k,l;
	while(t--)
	{
		for(i=0;i<=102;i++)
		{x[i]='\0';y[i]='\0';}
		carry=0;
		scanf("%s",x);
		scanf("%s",more);
		ln=strlen(x);
		lm=strlen(more);

		while(lm!=0)
		{
			more[ln-1]=more[lm-1];
			ln--;
			lm--;
		}
		for(i=0;i<ln;i++)
			more[i]='0';
		ln=strlen(x);
	
		for(i=ln-1;i>=0;i--)
		{
			if(x[i]>=more[i])
			{
				y[i]=(int)((int)x[i]-(int)more[i])+48;
			}
			else
			{
				x[i-1]=(int)((int)x[i-1]-1);
				l=(int)((int)x[i]+10-(int)more[i]);
				y[i]=l+48;
			}
		}
		i=0;
		while(y[i]=='0')
			i++;
		if(strlen(y)==i)
			printf("0");
		else
			for(l=i;l<=ln;l++)
				printf("%c",y[l]);
		printf("\n");
	}
	return 0;
}
3 Likes
3

thnx for helping.
i may be having problem in the addition part
will check