# Print modified array after executing the commands of addition and subtraction

Given an array of size ‘n’ and a given set of commands of size ‘m’. Every command consist of four integers q, l, r, k. These commands are of following types:

• If q = 0, add ‘k’ to all integers in range ‘a’ to ‘b'(1 <= a <= b <= n).
• If q = 1, subtract ‘k’ to all integers in range ‘a’ to ‘b'(1 <= a <= b <= n).

Note: Initially all the array elements are set to ‘0’ and array indexing is from ‘1’.

```Input : n = 5
commands[] = {{0 1 3 2}, {1 3 5 3},
{0 2 5 1}}
Output : 0 2 -1 -1 -3
Explanation
First command: Add 2 from index 1 to 3
>=  2 2 2 0 0
Second command: Subtract 3 from index 3 to 5
>= 2 2 -1 -3 -3
Third command: Add 1 from index 2 to 5
>= 2 3 0 -2 -2
```

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

Simple approach is to execute every command by iterating from left index(l) up-to the right index(r) and update every index according to given command. Time complexity of this approach is O(n*m)

Better approach is to use Fenwick tree(BIT) or segment tree. But it will only optimize upto log(n) time i.e., overall complexity would become O(m*log(n))

Efficient approach is to use simple mathematics. Since all commands can be handled as offline so we can store all updates in our temporary array and then execute it at the last.

• For command ‘0‘, add ‘+k‘ and ‘-k‘ in lth and (r+1)th index elements respectively.
• For command ‘1‘, add ‘-k‘ and ‘+k‘ in the lth and (r+1)th index elements respectively.

After that sum up all the elements for every index ‘i‘ starting from 1st index i.e., ai will contain the sum of all elements from 1 to ith index. This can easily be achieved with the help of dynamic programming.

## C++

 `// C++ program to find modified array ` `// after executing m commands/queries ` `#include ` `using` `namespace` `std; ` ` `  `// Update function for every command ` `void` `updateQuery(``int` `arr[], ``int` `n, ``int` `q, ``int` `l, ` `                 ``int` `r, ``int` `k) ` `{ ` `    ``// If q == 0, add 'k' and '-k' ` `    ``// to 'l-1' and 'r' index ` `    ``if` `(q == 0){ ` `        ``arr[l-1] += k; ` `        ``arr[r] += -k; ` `    ``} ` ` `  `    ``// If q == 1, add '-k' and 'k' ` `    ``// to 'l-1' and 'r' index ` `    ``else``{ ` `        ``arr[l-1] += -k; ` `        ``arr[r] += k; ` `    ``} ` `    ``return``; ` `} ` ` `  `// Function to generate the final ` `// array after executing all  ` `// commands ` `void` `generateArray(``int` `arr[], ``int` `n) ` `{ ` `    ``// Generate final array with the  ` `    ``// help of DP concept ` `    ``for` `(``int` `i = 1; i < n; ++i) ` `        ``arr[i] += arr[i-1]; ` `     `  `    ``return``; ` `} ` ` `  `// Driver program ` `int` `main() ` `{ ` `    ``int` `n = 5; ` `    ``int` `arr[n+1]; ` `    ``//Set all array elements to '0' ` `    ``memset``(arr, 0, ``sizeof``(arr)); ` ` `  `    ``int` `q = 0, l = 1, r = 3, k = 2; ` `    ``updateQuery(arr, n, q, l, r, k); ` ` `  `    ``q = 1 , l = 3, r = 5, k = 3; ` `    ``updateQuery(arr, n, q, l, r, k); ` ` `  `    ``q = 0 , l = 2, r = 5, k = 1; ` `    ``updateQuery(arr, n, q, l, r, k); ` ` `  `    ``// Generate final array ` `    ``generateArray(arr, n); ` ` `  `    ``// Printing the final modified array ` `    ``for` `(``int` `i = 0; i < n; ++i) ` `        ``cout << arr[i] << ``" "``; ` `    ``return` `0; ` `} `

## Java

 `// Java program to find modified array ` `// after executing m commands/queries ` `import` `java.util.Arrays; ` ` `  `class` `GFG { ` `     `  `    ``// Update function for every command ` `    ``static` `void` `updateQuery(``int` `arr[], ``int` `n,  ` `                  ``int` `q, ``int` `l, ``int` `r, ``int` `k) ` `    ``{ ` `         `  `        ``// If q == 0, add 'k' and '-k' ` `        ``// to 'l-1' and 'r' index ` `        ``if` `(q == ``0``){ ` `            ``arr[l-``1``] += k; ` `            ``arr[r] += -k; ` `        ``} ` `      `  `        ``// If q == 1, add '-k' and 'k' ` `        ``// to 'l-1' and 'r' index ` `        ``else``{ ` `            ``arr[l-``1``] += -k; ` `            ``arr[r] += k; ` `        ``} ` `         `  `        ``return``; ` `    ``} ` `      `  `    ``// Function to generate the final ` `    ``// array after executing all  ` `    ``// commands ` `    ``static` `void` `generateArray(``int` `arr[], ``int` `n) ` `    ``{ ` `        ``// Generate final array with the  ` `        ``// help of DP concept ` `        ``for` `(``int` `i = ``1``; i < n; ++i) ` `            ``arr[i] += arr[i-``1``]; ` `          `  `    ``} ` `    ``//driver code ` `    ``public` `static` `void` `main(String arg[]) ` `    ``{ ` `        ``int` `n = ``5``; ` `        ``int` `arr[] = ``new` `int``[n+``1``]; ` `         `  `        ``//Set all array elements to '0' ` `        ``Arrays.fill(arr, ``0``); ` `         `  `        ``int` `q = ``0``, l = ``1``, r = ``3``, k = ``2``; ` `        ``updateQuery(arr, n, q, l, r, k); ` `      `  `        ``q = ``1` `; l = ``3``; r = ``5``; k = ``3``; ` `        ``updateQuery(arr, n, q, l, r, k); ` `      `  `        ``q = ``0` `; l = ``2``; r = ``5``; k = ``1``; ` `        ``updateQuery(arr, n, q, l, r, k); ` `      `  `        ``// Generate final array ` `        ``generateArray(arr, n); ` `      `  `        ``// Printing the final modified array ` `        ``for` `(``int` `i = ``0``; i < n; ++i) ` `            ``System.out.print(arr[i]+``" "``); ` `    ``} ` `} ` ` `  `// This code is contributed by Anant Agarwal. `

## Python3

 `  `  `# Python3 program to find modified array ` `# after executing m commands/queries ` ` `  `# Update function for every command ` `def` `updateQuery(arr, n, q, l, r, k): ` ` `  `    ``# If q == 0, add 'k' and '-k' ` `    ``# to 'l-1' and 'r' index ` `    ``if` `(q ``=``=` `0``): ` `        ``arr[l ``-` `1``] ``+``=` `k ` `        ``arr[r] ``+``=` `-``k ` ` `  `    ``# If q == 1, add '-k' and 'k' ` `    ``# to 'l-1' and 'r' index ` `    ``else``: ` `        ``arr[l ``-` `1``] ``+``=` `-``k ` `        ``arr[r] ``+``=` `k ` `     `  `    ``return` ` `  `# Function to generate the final ` `# array after executing all commands ` `def` `generateArray(arr, n): ` ` `  `    ``# Generate final array with the  ` `    ``# help of DP concept ` `    ``for` `i ``in` `range``(``1``, n): ` `        ``arr[i] ``+``=` `arr[i ``-` `1``] ` `     `  `    ``return` ` `  `# Driver Code ` `n ``=` `5` `arr ``=` `[``0` `for` `i ``in` `range``(n ``+` `1``)] ` ` `  `# Set all array elements to '0' ` `q ``=` `0``; l ``=` `1``; r ``=` `3``; k ``=` `2` `updateQuery(arr, n, q, l, r, k) ` ` `  `q, l, r, k ``=` `1``, ``3``, ``5``, ``3` `updateQuery(arr, n, q, l, r, k); ` ` `  `q, l, r, k ``=` `0``, ``2``, ``5``, ``1` `updateQuery(arr, n, q, l, r, k) ` ` `  `# Generate final array ` `generateArray(arr, n) ` ` `  `# Printing the final modified array ` `for` `i ``in` `range``(n): ` `    ``print``(arr[i], end ``=` `" "``) ` `     `  `     `  `# This code is contributed by Anant Agarwal. `

## C#

 `// Program to find modified ` `// array after executing ` `// m commands/queries ` `using` `System; ` ` `  `class` `GFG { ` ` `  `    ``// Update function for every command ` `    ``static` `void` `updateQuery(``int``[] arr, ``int` `n, ``int` `q, ` `                            ``int` `l, ``int` `r, ``int` `k) ` `    ``{ ` ` `  `        ``// If q == 0, add 'k' and '-k' ` `        ``// to 'l-1' and 'r' index ` `        ``if` `(q == 0) { ` `            ``arr[l - 1] += k; ` `            ``arr[r] += -k; ` `        ``} ` ` `  `        ``// If q == 1, add '-k' and 'k' ` `        ``// to 'l-1' and 'r' index ` `        ``else` `{ ` `            ``arr[l - 1] += -k; ` `            ``arr[r] += k; ` `        ``} ` `        ``return``; ` `    ``} ` ` `  `    ``// Function to generate final ` `    ``// array after executing all ` `    ``// commands ` `    ``static` `void` `generateArray(``int``[] arr, ``int` `n) ` `    ``{ ` `        ``// Generate final array with ` `        ``// the help of DP concept ` `        ``for` `(``int` `i = 1; i < n; ++i) ` `            ``arr[i] += arr[i - 1]; ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 5; ` `        ``int``[] arr = ``new` `int``[n + 1]; ` ` `  `        ``// Set all array elements to '0' ` `        ``for` `(``int` `i = 0; i < arr.Length; i++) ` `            ``arr[i] = 0; ` ` `  `        ``int` `q = 0, l = 1, r = 3, k = 2; ` `        ``updateQuery(arr, n, q, l, r, k); ` ` `  `        ``q = 1; ` `        ``l = 3; ` `        ``r = 5; ` `        ``k = 3; ` `        ``updateQuery(arr, n, q, l, r, k); ` ` `  `        ``q = 0; ` `        ``l = 2; ` `        ``r = 5; ` `        ``k = 1; ` `        ``updateQuery(arr, n, q, l, r, k); ` ` `  `        ``// Generate final array ` `        ``generateArray(arr, n); ` ` `  `        ``// Printing the final modified array ` `        ``for` `(``int` `i = 0; i < n; ++i) ` `            ``Console.Write(arr[i] + ``" "``); ` `    ``} ` `} ` ` `  `// This code is contributed by Anant Agarwal. `

```Output: 2 3 0 -2 -2
```

Time complexity: O(Max(m,n))
Auxiliary space: O(n)

This article is contributed by Shubham Bansal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

My Personal Notes arrow_drop_up

Article Tags :
Practice Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.