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# Maximize count of 0s in left and 1s in right substring by splitting given Binary string

• Difficulty Level : Medium
• Last Updated : 21 May, 2021

Given binary string str, the task is to maximize the count of 0s in the left substring and 1s in the right substring by splitting the given binary string at any index. Print the sum of such 0s and 1s in the end.

Examples:

Input: str = “0011110011”
Output:
Explanation:
If a string is split at index 2, then Left substring = “00” and Right substring = “11110011”.
Therefore, the sum of the count of 0s in left substring and 1s in right substring is 2 + 6 = 8.
Input: str = “0001101111011”
Output: 11
Explanation:
If the string is split at index 3, then the Left substring is “000” and the right substring is “1101111011”.
Therefore, the sum of the count of 0s in left substring and 1s in right substring is 3 + 8 = 11.

Approach:

1. Count the number of ones in the given binary string str (say totalOnes).
2. Traverse the given string and keep the counts of 0s (say zero) and 1s (say one).
3. During the string traversal, update the maximum sum as:

maxSum = max(maxSum, zero + (totalOnes – one))

Below is the implementation of the above approach:

## C++

 `// C++ program for the above approach` `#include ``using` `namespace` `std;` `// Function to maximize the sum of the count``// of zeros and ones in the left and right``// substring``int` `maxSum(string& str)``{` `    ``int` `maximumSum = 0;` `    ``// To store the total ones``    ``int` `totalOnes;` `    ``// Count the total numbers of ones``    ``// in string str``    ``totalOnes = count(str.begin(),``                      ``str.end(), ``'1'``);` `    ``// To store the count of zeros and``    ``// ones while traversing string``    ``int` `zero = 0, ones = 0;` `    ``// Interate the given string and``    ``// update the maximum sum``    ``for` `(``int` `i = 0; str[i]; i++) {` `        ``if` `(str[i] == ``'0'``) {``            ``zero++;``        ``}``        ``else` `{``            ``ones++;``        ``}` `        ``// Update the maximum Sum``        ``maximumSum``            ``= max(``                ``maximumSum,``                ``zero + (totalOnes - ones));``    ``}` `    ``return` `maximumSum;``}` `// Driver Code``int` `main()``{``    ``// Given binary string``    ``string str = ``"011101"``;` `    ``// Function call``    ``cout << maxSum(str);``    ``return` `0;``}`

## Java

 `// Java program for the above approach``import` `java.util.*;` `class` `GFG {` `// Function to maximize the sum ``// of the count of zeros and ones ``// in the left and right substring``static` `int` `maxSum(String str)``{``    ``int` `maximumSum = ``0``;` `    ``// To store the total ones``    ``int` `totalOnes = ``0``;` `    ``// Count the total numbers of ones``    ``// in string str``    ``for``(``int` `i = ``0``; i < str.length(); i++)``    ``{``       ``if` `(str.charAt(i) == ``'1'``)``       ``{``           ``totalOnes++;``       ``}``    ``}``    ` `    ``// To store the count of zeros and``    ``// ones while traversing string``    ``int` `zero = ``0``, ones = ``0``;` `    ``// Interate the given string and``    ``// update the maximum sum``    ``for``(``int` `i = ``0``; i < str.length(); i++)``    ``{``       ``if` `(str.charAt(i) == ``'0'``)``       ``{``           ``zero++;``       ``}``       ``else``       ``{``           ``ones++;``       ``}``       ` `       ``// Update the maximum Sum``       ``maximumSum = Math.max(maximumSum,``                            ``zero + (totalOnes - ones));``    ``}``    ` `    ``return` `maximumSum;``}` `// Driver Code``public` `static` `void` `main(String args[])``{``    ` `    ``// Given binary string``    ``String str = ``"011101"``;` `    ``// Function call``    ``System.out.println(maxSum(str));``}``}` `// This code is contributed by rutvik_56`

## Python3

 `# Python3 program for the above approach` `# Function to maximize the sum of the count``# of zeros and ones in the left and right``# substring``def` `maxSum(``str``):` `    ``maximumSum ``=` `0` `    ``# To store the total ones` `    ``# Count the total numbers of ones``    ``# in str``    ``totalOnes ``=` `0``    ``for` `i ``in` `str``:``        ``if` `i ``=``=` `'1'``:``            ``totalOnes ``+``=` `1` `    ``# To store the count of zeros and``    ``# ones while traversing string``    ``zero ``=` `0``    ``ones ``=` `0` `    ``# Interate the given and``    ``# update the maximum sum``    ``i ``=` `0``    ``while` `i < ``len``(``str``):` `        ``if` `(``str``[i] ``=``=` `'0'``):``            ``zero ``+``=` `1``        ``else``:``            ``ones ``+``=` `1` `        ``# Update the maximum Sum``        ``maximumSum``=` `max``(maximumSum,zero ``+` `(totalOnes ``-` `ones))``        ``i ``+``=` `1` `    ``return` `maximumSum` `# Driver Code``if` `__name__ ``=``=` `'__main__'``:``    ``# Given binary string``    ``str` `=` `"011101"` `    ``# Function call``    ``print``(maxSum(``str``))` `# This code is contributed by mohit kumar 29`

## C#

 `// C# program for the above approach``using` `System;` `class` `GFG{` `// Function to maximize the sum``// of the count of zeros and ones``// in the left and right substring``static` `int` `maxSum(``string` `str)``{``    ``int` `maximumSum = 0;` `    ``// To store the total ones``    ``int` `totalOnes = 0;` `    ``// Count the total numbers of ones``    ``// in string str``    ``for``(``int` `i = 0; i < str.Length; i++)``    ``{``       ``if` `(str[i] == ``'1'``)``       ``{``           ``totalOnes++;``       ``}``    ``}``    ` `    ``// To store the count of zeros and``    ``// ones while traversing string``    ``int` `zero = 0, ones = 0;` `    ``// Interate the given string and``    ``// update the maximum sum``    ``for``(``int` `i = 0; i < str.Length; i++)``    ``{``       ``if` `(str[i] == ``'0'``)``       ``{``           ``zero++;``       ``}``       ``else``       ``{``           ``ones++;``       ``}``       ` `       ``// Update the maximum Sum``       ``maximumSum = Math.Max(maximumSum, zero +``                                   ``(totalOnes -``                                    ``ones));``    ``}``    ``return` `maximumSum;``}` `// Driver Code``public` `static` `void` `Main(``string` `[]args)``{``    ` `    ``// Given binary string``    ``string` `str = ``"011101"``;` `    ``// Function call``    ``Console.Write(maxSum(str));``}``}` `// This code is contributed by rutvik_56`

## Javascript

 ``
Output:
`5`

Time Complexity: O(N), where N is the length of the string.

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