how to find out the union of two character arrays?

Question Posted / prakashdasari

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how to find out the union of two character arrays?..

Answer / prakashdasari

char *str1,*str2,*res;
while(*str1!=NULL)
str++;
while(*str2!=NULL)
{
*str1 == *str2;
str1++;
str2++;
}
*str1 = '\0';
//so total string is in one string ie str1 itself;
//now i will remove duplicates from entire string
for(i=0;str[i]!=NULL;i++)
{
for(j=0;str[j]!=NULL;j++)
{
if(str[i]==str[j])
{
flag = 1;break;
}
else flag = 0;
}
if(flag == 0)
{
*res = str[i];
res++;
}
*res = '\0';
}
now resultant string (res) is union of two character
arrays....

Is This Answer Correct ?

6 Yes

1 No

how to find out the union of two character arrays?..

Answer / om

Input: str1 (size M), str2 (size N)
Output:- Union_string str3.

1. Take a auxillary interger array of size 128 and
initialize all its's enteries to zero.(becoz All printable
chacter has value in the range [0,127]. so 128)
int Aux[128]={0}; //O(128) TIME

2. set Couter = strlen(str1) + strlen(str2) +1 ;//extra one
for '\0' character..

3. now scan the first string str1 and put 1 on the index
value equal to str1[i] in auxillary array.If there were
already 1,then Counter--;
Aux[str1[i]]=1; //O(M) TIME

4. now scan the second string str2 and put 1 on the index
value equal to str2[i] in auxillary array.Similar to step 3.
If there were already 1,then Counter--;
Aux[str2[i]=1; //O(N) TIME

5. Now alloacte a memory of size equal to "Counter" for our
resulting union string str3.
char *str3=(char*)malloc(Counter);

6. now again scan the str1 followed by str2. and if any 1 is
found in Aux[str1[i]] or Aux[str2[i]] make it 0. and put
that character to union string str3.

int k=0;
for(int i=0; str1[i]!='\0' ;i++) //O(M)
if(Aux[str1[i]] ==1)
{
str3[k++]=str1[i];
Aux[str1[i]] =0;
}

for(int i=0; str2[i]!='\0' ;i++) //0(N)
if(Aux[str2[i]] ==1)
{
str3[k++]=str2[i];
Aux[str2[i]] =0;
}
str3[k]=\0';

and return str3.

// SO TOTAL O(MAX(M,N)) TIME COMPLEXITY ALGORITHM USING
CONSTANT SPACE OF SIZE 128.

Is This Answer Correct ?

2 Yes

2 No

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