# 11 Pattern Count | Samsung

### Question

Write a program to find the 11 pattern count. Given a string, your task is to find the number of patterns of form 11 where  represents any number of zeroes(minimum requirement is one 0) there should not be any other character except  0 in  sequence.

### Logic

• The logic is simple. When we encounter a character other than 1, we continue traversing the string.
• If 1 is encountered then check whether zeros are coming after that. We use Zcnt variable to count the number of zero.
• When we encounter 1 after repeating zeros, check whether the Zcnt is positive. If so then increment the count of 11 pattern count.
• Repeat the same procedure till we reach the end of the string.

### Program

```#include<stdio.h>
#include<string.h>
int main()
{
char s;
int i,j,t,n,Zcnt=0,count=0;
printf("enter the string");
scanf("%s",&s);
n=strlen(s);
/*ascii of
0 ->48
1-> 49 */
for(i=0;i<n;i++)
{
t=s[i];                 //Storing ascii of character
if(t==48 || t>57)
continue;           //continue if '0' or not a number
else
{
if(t==49)           //character is '1'
{
j=i+1;          //move one position forward
t=s[j];
while(t==48)    //character is '0'
{
Zcnt++;     //increment ZeroCount
j++;
t=s[j];
}
/*character is 1 and Zcnt is greater than zero*/
if(t==49&&Zcnt>0)
{
count++;   //count of 11 pattern
Zcnt=0;    //reset ZeroCount
}
}
}
i=j;                    //reset i
}
printf("%d",count);         //total 11 patterns
}
```

### Analysis

Time complexity – O(n) since we are traversing the whole string.

Space complexity- O(1) since we are not using any storage relative to the input.

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