Find all the patterns of “1(0+)1” in a given string | SET 1(General Approach)
A string contains patterns of the form 1(0+)1 where (0+) represents any non-empty consecutive sequence of 0’s. Count all such patterns. The patterns are allowed to overlap.
Note : It contains digits and lowercase characters only. The string is not necessarily a binary. 100201 is not a valid pattern.
One approach to solve the problem is discussed here, other using Regular expressions is given in Set 2
Examples:
Input : 1101001 Output : 2 Input : 100001abc101 Output : 2
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Let size of input string be n.
1. Iterate through index ‘0’ to ‘n-1’.
2. If we encounter a ‘1’, we iterate till the elements are ‘0’.
3. After the stream of zeros ends, we check whether we encounter a ‘1’ or not.
4. Keep on doing this till we reach the end of string.
Below is the implementation of the above method.
C++
/* Code to count 1(0+)1 patterns in a string */#include <bits/stdc++.h>using namespace std;/* Function to count patterns */int patternCount(string str){ /* Variable to store the last character*/ char last = str[0]; int i = 1, counter = 0; while (i < str.size()) { /* We found 0 and last character was '1', state change*/ if (str[i] == '0' && last == '1') { while (str[i] == '0') i++; /* After the stream of 0's, we got a '1', counter incremented*/ if (str[i] == '1') counter++; } /* Last character stored */ last = str[i]; i++; } return counter;}/* Driver Code */int main(){ string str = "1001ab010abc01001"; cout << patternCount(str) << endl; return 0;} |
Java
// Java Code to count 1(0+)1// patterns in a stringimport java.io.*;class GFG{ // Function to count patterns static int patternCount(String str) { /* Variable to store the last character*/ char last = str.charAt(0); int i = 1, counter = 0; while (i < str.length()) { /* We found 0 and last character was '1', state change*/ if (str.charAt(i) == '0' && last == '1') { while (str.charAt(i) == '0') i++; // After the stream of 0's, we // got a '1',counter incremented if (str.charAt(i) == '1') counter++; } /* Last character stored */ last = str.charAt(i); i++; } return counter; } // Driver Code public static void main (String[] args) { String str = "1001ab010abc01001"; System.out.println(patternCount(str)); }}// This code is contributed by vt_m. |
Python3
# Python3 code to count 1(0+)1 patterns in a# Function to count patternsdef patternCount(str): # Variable to store the last character last = str[0] i = 1; counter = 0 while (i < len(str)): # We found 0 and last character was '1', # state change if (str[i] == '0' and last == '1'): while (str[i] == '0'): i += 1 # After the stream of 0's, we got a '1', # counter incremented if (str[i] == '1'): counter += 1 # Last character stored last = str[i] i += 1 return counter# Driver Codestr = "1001ab010abc01001"ans = patternCount(str)print (ans) # This code is contributed by saloni1297 |
C#
// C# Code to count 1(0 + )1// patterns in a stringusing System;class GFG{ // Function to count patterns static int patternCount(String str) { // Variable to store the // last character char last = str[0]; int i = 1, counter = 0; while (i < str.Length) { // We found 0 and last // character was '1', // state change if (str[i] == '0' && last == '1') { while (str[i] == '0') i++; // After the stream of 0's, we // got a '1',counter incremented if (str[i] == '1') counter++; } // Last character stored last = str[i]; i++; } return counter; } // Driver Code public static void Main () { String str = "1001ab010abc01001"; Console.Write(patternCount(str)); }}// This code is contributed by nitin mittal |
PHP
<?php// PHP Code to count 1(0+)1 patterns// in a string// Function to count patternsfunction patternCount($str){ // Variable to store the // last character $last = $str[0]; $i = 1; $counter = 0; while ($i < strlen($str)) { // We found 0 and last character // was '1', state change if ($str[$i] == '0' && $last == '1') { while ($str[$i] == '0') $i++; // After the stream of 0's, // we got a '1', counter // incremented if ($str[$i] == '1') $counter++; } /* Last character stored */ $last = $str[$i]; $i++; } return $counter;} // Driver Code $str = "1001ab010abc01001"; echo patternCount($str) ;// This code is contributed by nitin mittal?> |
Javascript
<script>// javascript Code to count 1(0+)1// patterns in a string // Function to count patterns function patternCount(str) { /* Variable to store the last character*/ var last = str.charAt(0); var i = 1, counter = 0; while (i < str.length) { /* We found 0 and last character was '1', state change*/ if (str.charAt(i) == '0' && last == '1') { while (str.charAt(i) == '0') i++; // After the stream of 0's, we // got a '1',counter incremented if (str.charAt(i) == '1') counter++; } /* Last character stored */ last = str.charAt(i); i++; } return counter; } // Driver Code var str = "1001ab010abc01001"; document.write(patternCount(str));// This code is contributed by 29AjayKumar</script> |
Output :
2
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