Given a binary string of 0s and 1s. The task is to find the maximum difference between the number of 0s and number of 1s in any sub-string of the given binary string. That is maximize ( number of 0s – number of 1s ) for any sub-string in the given binary string.
Examples:
Input : S = "11000010001" Output : 6 From index 2 to index 9, there are 7 0s and 1 1s, so number of 0s - number of 1s is 6. Input : S = "1111" Output : -1
We have discussed Dynamic Programming approach in below post :
Maximum difference of zeros and ones in binary string | Set 1.
In the post we seen an efficient method that work in O(n) time and in O(1) extra space. Idea behind that if we convert all zeros into 1 and all ones into -1.now our problem reduces to find out the maximum sum sub_array Using Kadane’s Algorithm.
Input : S = "11000010001" After converting '0' into 1 and '1' into -1 our S Look Like S = -1 -1 1 1 1 1 -1 1 1 1 -1 Now we have to find out Maximum Sum sub_array that is : 6 is that case Output : 6
Below is the implementation of above idea.
C++
// CPP Program to find the length of // substring with maximum difference of // zeros and ones in binary string. #include <iostream> using namespace std; // Returns the length of substring with // maximum difference of zeroes and ones // in binary string int findLength(string str, int n) { int current_sum = 0; int max_sum = 0; // traverse a binary string from left // to right for ( int i = 0; i < n; i++) { // add current value to the current_sum // according to the Character // if it's '0' add 1 else -1 current_sum += (str[i] == '0' ? 1 : -1); if (current_sum < 0) current_sum = 0; // update maximum sum max_sum = max(current_sum, max_sum); } // return -1 if string does not contain // any zero that means all ones // otherwise max_sum return max_sum == 0 ? -1 : max_sum; } // Driven Program int main() { string s = "11000010001" ; int n = 11; cout << findLength(s, n) << endl; return 0; } |
Java
// Java Program to find the length of // substring with maximum difference of // zeroes and ones in binary string. import java.util.*; import java.lang.*; import java.io.*; class GFG { // Find the length of substring with maximum // difference of zeros and ones in binary // string public static int findLength(String str, int n) { int current_sum = 0 ; int max_sum = 0 ; // traverse a binary string from left to right for ( int i = 0 ; i < n; i++) { // add current value to the current_sum // according to the Character // if it's '0' add 1 else -1 current_sum += (str.charAt(i) == '0' ? 1 : - 1 ); if (current_sum < 0 ) current_sum = 0 ; // update maximum sum max_sum = Math.max(current_sum, max_sum); } // return -1 if string does not contain any zero // that means string contains all ones otherwise max_sum return max_sum == 0 ? - 1 : max_sum; } public static void main(String[] args) { String str = "11000010001" ; int n = str.length(); System.out.println(findLength(str, n)); } } |
Python3
# Python Program to find the length of # substring with maximum difference of # zeros and ones in binary string. # Returns the length of substring with # maximum difference of zeroes and ones # in binary string def findLength(string, n): current_sum = 0 max_sum = 0 # traverse a binary string from left # to right for i in range (n): # add current value to the current_sum # according to the Character # if it's '0' add 1 else -1 current_sum + = ( 1 if string[i] = = '0' else - 1 ) if current_sum < 0 : current_sum = 0 # update maximum sum max_sum = max (current_sum, max_sum) # return -1 if string does not contain # any zero that means all ones # otherwise max_sum return max_sum if max_sum else 0 # Driven Program s = "11000010001" n = 11 print (findLength(s, n)) # This code is contributed by Ansu Kumari. |
C#
// C# Program to find the length of // substring with maximum difference of // zeroes and ones in binary string. using System; class GFG { // Find the length of substring with // maximum difference of zeros and // ones in binary string public static int findLength( string str, int n) { int current_sum = 0; int max_sum = 0; // traverse a binary string // from left to right for ( int i = 0; i < n; i++) { // add current value to the current_sum // according to the Character // if it's '0' add 1 else -1 current_sum += (str[i] == '0' ? 1 : -1); if (current_sum < 0) { current_sum = 0; } // update maximum sum max_sum = Math.Max(current_sum, max_sum); } // return -1 if string does not contain // any zero that means string contains // all ones otherwise max_sum return max_sum == 0 ? -1 : max_sum; } // Driver Code public static void Main( string [] args) { string str = "11000010001" ; int n = str.Length; Console.WriteLine(findLength(str, n)); } } // This code is contributed by Shrikant13 |
PHP
<?php // PHP Program to find the length of // substring with maximum difference of // zeros and ones in binary string. // Returns the length of substring with // maximum difference of zeroes and ones // in binary string function findLength( $str , $n ) { $current_sum = 0; $max_sum = 0; // traverse a binary string // from left to right for ( $i = 0; $i < $n ; $i ++) { // add current value to the current_sum // according to the Character // if it's '0' add 1 else -1 $current_sum += ( $str [ $i ] == '0' ? 1 : -1); if ( $current_sum < 0) $current_sum = 0; // update maximum sum $max_sum = max( $current_sum , $max_sum ); } // return -1 if string does not contain // any zero that means all ones // otherwise max_sum return $max_sum == 0 ? -1 : $max_sum ; } // Driver Code $s = "11000010001" ; $n = 11; echo findLength( $s , $n ), "\n" ; // This code is contributed by aj_36 ?> |
Javascript
<script> // JavaScript program to find the length of // substring with maximum difference of // zeroes and ones in binary string. // Find the length of substring with // maximum difference of zeros and // ones in binary string function findLength(str, n) { let current_sum = 0; let max_sum = 0; // traverse a binary string // from left to right for (let i = 0; i < n; i++) { // add current value to the current_sum // according to the Character // if it's '0' add 1 else -1 current_sum += (str[i] == '0' ? 1 : -1); if (current_sum < 0) { current_sum = 0; } // update maximum sum max_sum = Math.max(current_sum, max_sum); } // return -1 if string does not contain // any zero that means string contains // all ones otherwise max_sum return max_sum == 0 ? -1 : max_sum; } // Driver Code let str = "11000010001" ; let n = str.length; document.write(findLength(str, n)); // This code is contributed by chinmoy1997pal. </script> |
6
Time Complexity: O(n)
Space complexity: O(n), since string gets copied when we pass it to a function.
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