# Deletions of “01” or “10” in binary string to make it free from “01” or “10”

Given a binary string **str**, the task is to find the count of deletion of the sub-string **“01”** or **“10”** from the string so that the given string is free from these sub-strings. Print the minimum number of deletions.

**Examples:**

Input:str = “11010”

Output:2

The resultant string will be “1”

Input:str = “1000101”

Output:3

Resultant string, str = “0”

**Approach: ** We are deleting **“01”** and **“10”** and the binary string contains only characters **‘0’** and **‘1’**. Therefore, minimum number of deletions will be equal to the minimum of the count of ‘0’ and ‘1’.

Below is the implementation of the above approach:

## C++

`// C++ implementation of the approach ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `// Function to return the count of deletions ` `// of sub-strings "01" or "10" ` `int` `substrDeletion(string str, ` `int` `len) ` `{ ` ` ` ` ` `// To store the count of 0s and 1s ` ` ` `int` `count0 = 0, count1 = 0; ` ` ` ` ` `for` `(` `int` `i = 0; i < len; i++) { ` ` ` `if` `(str[i] == ` `'0'` `) ` ` ` `count0++; ` ` ` `else` ` ` `count1++; ` ` ` `} ` ` ` ` ` `return` `min(count0, count1); ` `} ` ` ` `// Driver code ` `int` `main() ` `{ ` ` ` `string str = ` `"010"` `; ` ` ` `int` `len = str.length(); ` ` ` `cout << substrDeletion(str, len); ` ` ` ` ` `return` `0; ` `} ` |

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## Java

`// Java implementation of the approach ` `class` `GFG ` `{ ` ` ` `// Function to return the count of deletions ` `// of sub-strings "01" or "10" ` `static` `int` `substrDeletion(String str, ` `int` `len) ` `{ ` ` ` ` ` `// To store the count of 0s and 1s ` ` ` `int` `count0 = ` `0` `, count1 = ` `0` `; ` ` ` ` ` `for` `(` `int` `i = ` `0` `; i < len; i++) ` ` ` `{ ` ` ` `if` `(str.charAt(i) == ` `'0'` `) ` ` ` `count0++; ` ` ` `else` ` ` `count1++; ` ` ` `} ` ` ` ` ` `return` `Math.min(count0, count1); ` `} ` ` ` `// Driver code ` `public` `static` `void` `main(String[] args) ` `{ ` ` ` `String str = ` `"010"` `; ` ` ` `int` `len = str.length(); ` ` ` `System.out.println(substrDeletion(str, len)); ` `} ` `} ` ` ` `// This code is contributed by Code_Mech. ` |

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## Python3

`# Python3 implementation of the approach ` ` ` `# Function to return the count of ` `# deletions of sub-strings "01" or "10" ` `def` `substrDeletion(string, length) : ` ` ` ` ` `# To store the count of 0s and 1s ` ` ` `count0 ` `=` `0` `; ` ` ` `count1 ` `=` `0` `; ` ` ` ` ` `for` `i ` `in` `range` `(length) : ` ` ` `if` `(string[i] ` `=` `=` `'0'` `) : ` ` ` `count0 ` `+` `=` `1` `; ` ` ` `else` `: ` ` ` `count1 ` `+` `=` `1` `; ` ` ` ` ` `return` `min` `(count0, count1); ` ` ` `# Driver code ` `if` `__name__ ` `=` `=` `"__main__"` `: ` ` ` ` ` `string ` `=` `"010"` `; ` ` ` `length ` `=` `len` `(string); ` ` ` ` ` `print` `(substrDeletion(string, length)); ` ` ` `# This code is contributed by Ryuga ` |

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## C#

`// C# implementation of the approach ` `using` `System; ` ` ` `class` `GFG ` `{ ` ` ` `// Function to return the count of deletions ` `// of sub-strings "01" or "10" ` `static` `int` `substrDeletion(` `string` `str, ` `int` `len) ` `{ ` ` ` ` ` `// To store the count of 0s and 1s ` ` ` `int` `count0 = 0, count1 = 0; ` ` ` ` ` `for` `(` `int` `i = 0; i < len; i++) ` ` ` `{ ` ` ` `if` `(str[i] == ` `'0'` `) ` ` ` `count0++; ` ` ` `else` ` ` `count1++; ` ` ` `} ` ` ` ` ` `return` `Math.Min(count0, count1); ` `} ` ` ` `// Driver code ` `public` `static` `void` `Main() ` `{ ` ` ` `string` `str = ` `"010"` `; ` ` ` `int` `len = str.Length; ` ` ` `Console.Write(substrDeletion(str, len)); ` `} ` `} ` ` ` `// This code is contributed by Ita_c. ` |

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**Output:**

1

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