Find all the patterns of “1(0+)1” in a given string | SET 2(Regular Expression Approach)
In Set 1, we have discussed general approach for counting the patterns of the form 1(0+)1 where (0+) represents any non-empty consecutive sequence of 0’s.In this post, we will discuss regular expression approach to count the same. Examples:
Input : 1101001 Output : 2 Input : 100001abc101 Output : 2
Below is one of the regular expression for above pattern
Hence, whenever we found a match, we increase counter for counting the pattern.As last character of a match will always ‘1’, we have to again start searching from that index.
Time Complexity: O(n)
Auxiliary Space: O(1)
Related Articles :
- Regular Expression Java
- Extracting each word from a String using Regex
- Check if a given string is a valid number (Integer or Floating Point)
- Print first letter of each word in a string using regex
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