Python Program to Count number of binary strings without consecutive 1’

In this article, we will learn about the solution to the problem statement given below.

Problem statement − We are given a positive integer N, we need to count all possible distinct binary strings available with length N such that no consecutive 1’s exist in the string.

Now let’s observe the solution in the implementation below −

Example

# count the number of strings
def countStrings(n):
   a=[0 for i in range(n)]
   b=[0 for i in range(n)]
   a[0] = b[0] = 1
   for i in range(1,n):
      a[i] = a[i-1] + b[i-1]
      b[i] = a[i-1]
   return a[n-1] + b[n-1]
# main
n=5
print("The number of strings: ",countStrings(n))

Output

The number of strings: 13

All the variables are declared in the local scope and their references are seen in the figure above.

Conclusion

In this article, we have learned about how we can make a Python Program to Count number of binary strings without consecutive 1’