# Check if every pair of 1 in the array is at least K length apart from each other

Given a binary array and an integer K, check if every pair of 1 in the array is at least K length apart from each other. Return true if the condition holds, otherwise return false.

Examples:

Input: arr = [1, 0, 0, 0, 1, 0, 0, 1, 0, 0], K = 2.
Output: True
Explanation:
Every 1 in the array is at least K distance apart from each other.

Input: [1, 0, 1, 0, 1, 1], K = 1
Output: False
Explanation:
The fifth 1 and sixth 1 are not apart from each other. Hence, the output is false.

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

To solve the problem mentioned above we have to check the distance between each pair of adjacent 1. Find the first position of 1 then iterate through the rest of the array and increment distance if it’s 0 otherwise perform check operation if the distance is less than k and reset the count to 0 again.

Below is the implementation of the above approach:

## C++

 `// C++ implementation to Check if every pair of 1 in ` `// the array is at least K length from each other ` ` `  `#include ` `using` `namespace` `std; ` ` `  `// Function to check distance ` `bool` `kLengthApart(vector<``int``>& nums, ``int` `k) ` `{ ` `    ``// Find first position of 1 ` `    ``int` `pos = 0, count = 0; ` ` `  `    ``while` `(pos < nums.size() && nums[pos] == 0) ` `        ``pos++; ` ` `  `    ``// Iterate through the rest of array ` `    ``for` `(``int` `i = pos + 1; i < nums.size(); i++) { ` `        ``// Increment distance if its 0 ` `        ``if` `(nums[i] == 0) ` `            ``count++; ` ` `  `        ``// Check if the distance is less than k ` `        ``else` `{ ` `            ``if` `(count < k) ` `                ``return` `false``; ` ` `  `            ``// Reset count to 0 ` `            ``count = 0; ` `        ``} ` `    ``} ` ` `  `    ``// Return the result ` `    ``return` `true``; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``vector<``int``> nums = { 1, 0, 0, 0, 1, 0, 0, 1, 0, 0 }; ` `    ``int` `k = 2; ` ` `  `    ``bool` `ans = kLengthApart(nums, k); ` `    ``if` `(ans == 1) ` `        ``cout << ``"True"` `<< endl; ` ` `  `    ``else` `        ``cout << ``"False"` `<< endl; ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java implementation to check if  ` `// every pair of 1 in the array is  ` `// at least K length from each other  ` `class` `Main{ ` `     `  `// Function to check distance  ` `public` `static` `boolean` `kLengthApart(``int``[] nums, ` `                                   ``int` `k)  ` `{  ` `     `  `    ``// Find first position of 1  ` `    ``int` `pos = ``0``, count = ``0``;  ` ` `  `    ``while` `(pos < nums.length && nums[pos] == ``0``)  ` `        ``pos++;  ` ` `  `    ``// Iterate through the rest of array  ` `    ``for``(``int` `i = pos + ``1``; i < nums.length; i++) ` `    ``{ ` `         `  `       ``// Increment distance if its 0  ` `       ``if` `(nums[i] == ``0``)  ` `           ``count++;  ` `            `  `       ``// Check if the distance is less than k  ` `       ``else` `       ``{  ` `           ``if` `(count < k)  ` `               ``return` `false``;  ` `                `  `           ``// Reset count to 0  ` `           ``count = ``0``;  ` `       ``}  ` `    ``}  ` `     `  `    ``// Return the result  ` `    ``return` `true``;  ` `}  ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int``[] nums = { ``1``, ``0``, ``0``, ``0``, ``1``,  ` `                   ``0``, ``0``, ``1``, ``0``, ``0` `};  ` `    ``int` `k = ``2``;  ` `    ``boolean` `ans = kLengthApart(nums, k);  ` `     `  `    ``if` `(ans)  ` `        ``System.out.println(``"True"``); ` ` `  `    ``else` `        ``System.out.println(``"False"``); ` `} ` `} ` ` `  `// This code is contributed by divyeshrabadiya07 `

## Python3

 `# Python3 implementation to check if  ` `# every pair of 1 in the array is  ` `# at least K length from each other  ` ` `  `# Function to check distance ` `def` `kLengthApart(nums, k): ` `     `  `    ``# Find first position of 1  ` `    ``pos ``=` `0` `    ``count ``=` `0` `     `  `    ``while` `(pos < ``len``(nums) ``and` `nums[pos] ``=``=` `0``): ` `        ``pos ``+``=` `1` `         `  `    ``# Iterate through the rest of list ` `    ``for` `i ``in` `range``(pos ``+` `1``, ``len``(nums)): ` `         `  `        ``# Increment distance if its 0  ` `        ``if` `nums[i] ``=``=` `0``: ` `            ``count ``+``=` `1` `             `  `        ``# Check if the distance is less than k  ` `        ``else` `: ` `            ``if` `count < k: ` `                ``return` `False` `                 `  `            ``# Reset count to 0  ` `            ``count ``=` `0` `             `  `        ``# Return the result  ` `    ``return` `True` `     `  `# Driver Code ` `if` `__name__ ``=``=` `"__main__"``: ` `      `  `    ``nums ``=` `[ ``1``, ``0``, ``0``, ``0``, ``1``, ``0``, ``0``, ``1``, ``0``, ``0` `] ` `    ``k ``=` `2` `     `  `    ``print``(kLengthApart(nums, k)) ` ` `  `# This code is contributed by rutvik_56 `

## C#

 `// C# implementation to check if  ` `// every pair of 1 in the array is  ` `// at least K length from each other  ` `using` `System; ` ` `  `class` `GFG{ ` `     `  `// Function to check distance  ` `public` `static` `bool` `kLengthApart(``int``[] nums, ` `                                ``int` `k)  ` `{  ` `     `  `    ``// Find first position of 1  ` `    ``int` `pos = 0, count = 0;  ` ` `  `    ``while` `(pos < nums.Length && nums[pos] == 0)  ` `        ``pos++;  ` ` `  `    ``// Iterate through the rest of array  ` `    ``for``(``int` `i = pos + 1; i < nums.Length; i++) ` `    ``{ ` `        `  `       ``// Increment distance if its 0  ` `       ``if` `(nums[i] == 0)  ` `           ``count++;  ` `            `  `       ``// Check if the distance is  ` `       ``// less than k  ` `       ``else` `       ``{  ` `           ``if` `(count < k)  ` `               ``return` `false``;  ` `            `  `           ``// Reset count to 0  ` `           ``count = 0;  ` `       ``}  ` `    ``}  ` `     `  `    ``// Return the result  ` `    ``return` `true``;  ` `}  ` ` `  `// Driver Code ` `public` `static` `void` `Main() ` `{ ` `    ``int``[] nums = { 1, 0, 0, 0, 1,  ` `                   ``0, 0, 1, 0, 0 };  ` `    ``int` `k = 2;  ` `    ``bool` `ans = kLengthApart(nums, k);  ` `     `  `    ``if` `(ans)  ` `        ``Console.Write(``"True"``); ` `    ``else` `        ``Console.Write(``"False"``); ` `} ` `} ` ` `  `// This code is contributed by chitranayal `

Output:

```True
```

Time Complexity: O(n)
Auxiliary Space: O(1)

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