Given a string of 0 and 1, we need to check that the given string is valid or not. The given string is valid when there is no zero is present in between 1’s. For example, 1111, 0000111110, 1111000 are valid strings but 01010011, 01010, 101 are not.
One approach to solve the problem is discussed here, other using Regular expressions is given Set 2
Input : 100 Output : VALID Input : 1110001 Output : NOT VALID There is 0 between 1s Input : 00011 Output : VALID
- Find first occurrence of 1 in string. Let it be first.
- Find last occurrence of 1 in string. Let it be last.
- Run a loop from first to last and return false if there is a 0. If no 0 found, return true.
- Find all the patterns of "1(0+)1" in a given string | SET 1(General Approach)
- Extract maximum numeric value from a given string | Set 1 (General approach)
- Check if a binary string has a 0 between 1s or not | Set 2 (Regular Expression Approach)
- Check if a given string is a valid number (Integer or Floating Point) | SET 1(Basic approach)
- Check if a given string is a valid number (Integer or Floating Point) in Java | SET 2 (Regular Expression approach)
- Python | Check if a given string is binary string or not
- Check if all the 1's in a binary string are equidistant or not
- Check if a binary string contains consecutive same or not
- Check divisibility of binary string by 2^k
- Check if a binary string has two consecutive occurrences of one everywhere
- Check if a binary string contains all permutations of length k
- Check if it is possible to rearrange a binary string with alternate 0s and 1s
- Check if an encoding represents a unique binary string
- Check whether a binary string can be formed by concatenating given N numbers sequentially
- Extract maximum numeric value from a given string | Set 2 (Regex approach)
Suppose we have a string: 01111011110000
Now take two variables say A and B. run a loop for 0 to length of the string and point A
to the first occurrence of 1, after that again run a loop from length of the string to 0
and point second variable to the last occurrence of 1.
So A = 1 (Position of first ‘1’ is the string) and B = 9 (last occurrence of ‘1’).
Now run a loop from A to B and check that ‘0’ is present between 1 or not, if “YES” than
set flag to 1 and break the loop, else set flag to 0.
In this case flag will set to 1 as the given string is not valid and print “NOT VALID”.
Time Complexity : O(n)
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Improved By : Sam007