Given an array **arr[]** and an integer **K**, the task is to find the minimum number of operations required to change an array **B** of size **N** containing all zeros such that every element of B is greater than or equal to arr. i.e., arr[i] >= B[i]. In any operation, you can choose a subarray of B of size K and increment all the elements of the subarray by 1.**Examples:**

Input:arr[] = {1, 2, 3, 4, 5}, K = 2Output:9Explanation:

At first B[] = {0, 0, 0, 0, 0} operations = 0

Increment subarray a[1:2] by 1 => B = {1, 1, 0, 0, 0}, operations = 1

Increment subarray a[2:3] by 1 => B = {1, 2, 1, 0, 0}, operations = 2

Increment subarray a[3:4] by 2 => B = {1, 2, 3, 2, 0}, operations = 4

Increment subarray a[4:5] by 5 => B = {1, 2, 3, 7, 5}, operations = 9

Therefore, count of such operations required is 9.Input:arr[] = {2, 3, 1}, K = 3Output:3Explanation:

Incrementing the entire array by 3

**Approach:** The idea is to increment the subarray of size K whenever there is a B[i] is less than arr[i] and also increment the count of such operations by 1 at each step. To increment the subarray of size K use the Difference array for Range Query update in O(1).

Below is the implementation of the above approach:

## C++

`// C++ implementation to find the ` `// minimum number of operations ` `// required to change an array of` `// all zeros such that every element` `// is greater than the given array` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Function to find the minimum ` `// number of operations required` `// to change all the array of zeros` `// such that every element is greater` `// than the given array` `int` `find_minimum_operations(` `int` `n, ` `int` `b[],` ` ` `int` `k)` `{` ` ` ` ` `// Declaring the difference` ` ` `// array of size N` ` ` `int` `d[n + 1] = {0};` ` ` `// Number of operations` ` ` `int` `operations = 0, need;` ` ` `for` `(` `int` `i = 0; i < n; i++)` ` ` `{` ` ` ` ` `// First update the D[i] value ` ` ` `// with the previous value` ` ` `if` `(i > 0)` ` ` `{` ` ` `d[i] += d[i - 1];` ` ` `}` ` ` ` ` `// The index i has to be incremented` ` ` `if` `(b[i] > d[i])` ` ` `{` ` ` ` ` `// We have to perform ` ` ` `// (b[i]-d[i]) operations more` ` ` `operations += b[i] - d[i];` ` ` `need = b[i] - d[i];` ` ` `// Increment the range` ` ` `// i to i + k by need` ` ` `d[i] += need;` ` ` `// Check if i + k is valid index` ` ` `if` `(i + k <= n)` ` ` `{` ` ` `d[i + k]-= need;` ` ` `}` ` ` `}` ` ` `}` ` ` `cout << operations << endl;` `}` `// Driver Code` `int` `main()` `{` ` ` `int` `n = 5;` ` ` `int` `b[] = { 1, 2, 3, 4, 5 };` ` ` `int` `k = 2;` ` ` ` ` `// Function Call` ` ` `find_minimum_operations(n, b, k);` ` ` ` ` `return` `0;` `}` `// This code is contributed by shubhamsingh10` |

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## Java

`// Java implementation to find the ` `// minimum number of operations ` `// required to change an array of` `// all zeros such that every element` `// is greater than the given array` `class` `GFG{` `// Function to find the minimum ` `// number of operations required` `// to change all the array of zeros` `// such that every element is greater` `// than the given array` `static` `void` `find_minimum_operations(` `int` `n, ` `int` `b[],` ` ` `int` `k)` `{` ` ` ` ` `// Declaring the difference` ` ` `// array of size N` ` ` `int` `d[] = ` `new` `int` `[n + ` `1` `];` ` ` `// Number of operations` ` ` `int` `i, operations = ` `0` `, need;` ` ` `for` `(i = ` `0` `; i < n; i++)` ` ` `{` ` ` ` ` `// First update the D[i] value ` ` ` `// with the previous value` ` ` `if` `(i > ` `0` `)` ` ` `{` ` ` `d[i] += d[i - ` `1` `];` ` ` `}` ` ` ` ` `// The index i has to be incremented` ` ` `if` `(b[i] > d[i])` ` ` `{` ` ` ` ` `// We have to perform ` ` ` `// (b[i]-d[i]) operations more` ` ` `operations += b[i] - d[i];` ` ` `need = b[i] - d[i];` ` ` `// Increment the range` ` ` `// i to i + k by need` ` ` `d[i] += need;` ` ` `// Check if i + k is valid index` ` ` `if` `(i + k <= n)` ` ` `{` ` ` `d[i + k]-= need;` ` ` `}` ` ` `}` ` ` `}` ` ` `System.out.println(operations);` `}` `// Driver Code` `public` `static` `void` `main (String []args)` `{` ` ` `int` `n = ` `5` `;` ` ` `int` `b[] = { ` `1` `, ` `2` `, ` `3` `, ` `4` `, ` `5` `};` ` ` `int` `k = ` `2` `;` ` ` ` ` `// Function Call` ` ` `find_minimum_operations(n, b, k);` `}` `}` `// This code is contributed by chitranayal` |

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## Python3

`# Python3 implementation to find the ` `# minimum number of operations required ` `# to change an array of all zeros ` `# such that every element is greater than` `# the given array` `# Function to find the minimum ` `# number of operations required` `# to change all the array of zeros` `# such that every element is greater` `# than the given array` `def` `find_minimum_operations(n, b, k):` ` ` `# Declaring the difference` ` ` `# array of size N` ` ` `d ` `=` `[` `0` `for` `i ` `in` `range` `(n ` `+` `1` `)] ` ` ` `# Number of operations` ` ` `operations ` `=` `0` ` ` `for` `i ` `in` `range` `(n):` ` ` `# First update the D[i] value with` ` ` `# the previous value` ` ` `d[i]` `+` `=` `d[i` `-` `1` `]` ` ` `# The index i has to be incremented` ` ` `if` `b[i]>d[i]:` ` ` `# We have to perform ` ` ` `# (b[i]-d[i]) operations more` ` ` `operations` `+` `=` `(b[i]` `-` `d[i])` ` ` `need ` `=` `(b[i]` `-` `d[i]) ` ` ` `# Increment the range` ` ` `# i to i + k by need` ` ` `d[i]` `+` `=` `need` ` ` `# Check if i + k is valid index` ` ` `if` `i ` `+` `k<` `=` `n:` ` ` `d[i ` `+` `k]` `-` `=` `need` ` ` `return` `operations` `# Driver Code` `if` `__name__ ` `=` `=` `"__main__"` `:` ` ` `n ` `=` `5` ` ` `b ` `=` `[` `1` `, ` `2` `, ` `3` `, ` `4` `, ` `5` `]` ` ` `k ` `=` `2` ` ` ` ` `# Function Call` ` ` `print` `(find_minimum_operations(n, b, k))` |

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## C#

`// C# implementation to find the ` `// minimum number of operations ` `// required to change an array of` `// all zeros such that every element` `// is greater than the given array` `using` `System;` `class` `GFG{` ` ` `// Function to find the minimum ` `// number of operations required` `// to change all the array of zeros` `// such that every element is greater` `// than the given array` `static` `void` `find_minimum_operations(` `int` `n, ` `int` `[] b,` ` ` `int` `k)` `{` ` ` ` ` `// Declaring the difference` ` ` `// array of size N` ` ` `int` `[] d = ` `new` `int` `[n + 1];` ` ` ` ` `// Number of operations` ` ` `int` `i, operations = 0, need;` ` ` ` ` `for` `(i = 0; i < n; i++)` ` ` `{` ` ` ` ` `// First update the D[i] value ` ` ` `// with the previous value` ` ` `if` `(i > 0)` ` ` `{` ` ` `d[i] += d[i - 1];` ` ` `}` ` ` ` ` `// The index i has to be incremented` ` ` `if` `(b[i] > d[i])` ` ` `{` ` ` ` ` `// We have to perform ` ` ` `// (b[i]-d[i]) operations more` ` ` `operations += b[i] - d[i];` ` ` ` ` `need = b[i] - d[i];` ` ` ` ` `// Increment the range` ` ` `// i to i + k by need` ` ` `d[i] += need;` ` ` ` ` `// Check if i + k is valid index` ` ` `if` `(i + k <= n)` ` ` `{` ` ` `d[i + k]-= need;` ` ` `}` ` ` `}` ` ` `}` ` ` `Console.Write(operations);` `}` ` ` `// Driver Code` `public` `static` `void` `Main (` `string` `[]args)` `{` ` ` `int` `n = 5;` ` ` `int` `[] b = { 1, 2, 3, 4, 5 };` ` ` `int` `k = 2;` ` ` ` ` `// Function Call` ` ` `find_minimum_operations(n, b, k);` `}` `}` ` ` `// This code is contributed by rock_cool` |

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**Output:**

9

**Time Complexity: O(N)**

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