# Sum of all Perfect Cubes lying in the range [L, R] for Q queries

• Last Updated : 05 Apr, 2021

Given Q queries in the form of 2D array arr[][] whose every row consists of two numbers L and R which signifies the range [L, R], the task is to find the sum of all perfect cubes lying in this range.
Examples:

Input: Q = 2, arr[][] = {{4, 9}, {4, 44}}
Output: 8 35
From 4 to 9: only 8 is the perfect cube. Therefore, 8 is the ans
From 4 to 44: 8, and 27 are the perfect cubes. Therefore, 8 + 27 = 35
Input: Q = 4, arr[][] = {{ 1, 10 }, { 1, 100 }, { 2, 25 }, { 4, 50 }}
Output: 9 100 8 35

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Approach: The idea is to use a prefix sum array

1. The sum all cubes are precomputed and stored in an array pref[] so that every query can be answered in O(1) time.
2. Every ith index in the pref[] array represents the sum of perfect cubes from 1 to that number.
3. Therefore, the sum of perfect cubes from the given range â€˜Lâ€™ to â€˜Râ€™ can be found as from the prefix sum array pref[].

Below is the implementation of the above approach:

## C++

 `// C++ program to find the sum of all``// perfect cubes in the given range` `#include ``#define ll int``using` `namespace` `std;` `// Array to precompute the sum of cubes``// from 1 to 100010 so that for every``// query, the answer can be returned in O(1).``long` `long` `pref[100010];` `// Function to check if a number is``// a perfect Cube or not``int` `isPerfectCube(``long` `long` `int` `x)``{``    ``// Find floating point value of``    ``// cube root of x.``    ``long` `double` `cr = round(cbrt(x));` `    ``// If cube root of x is cr``    ``// return the x, else 0``    ``return` `(cr * cr * cr == x) ? x : 0;``}` `// Function to precompute the perfect``// Cubes upto 100000.``void` `compute()``{``    ``for` `(``int` `i = 1; i <= 100000; ++i) {``        ``pref[i] = pref[i - 1]``                  ``+ isPerfectCube(i);``    ``}``}` `// Function to print the sum for each query``void` `printSum(``int` `L, ``int` `R)``{``    ``int` `sum = pref[R] - pref[L - 1];``    ``cout << sum << ``" "``;``}` `// Driver code``int` `main()``{``    ``// To calculate the precompute function``    ``compute();` `    ``int` `Q = 4;``    ``int` `arr[][2] = { { 1, 10 },``                     ``{ 1, 100 },``                     ``{ 2, 25 },``                     ``{ 4, 50 } };` `    ``// Calling the printSum function``    ``// for every query``    ``for` `(``int` `i = 0; i < Q; i++) {``        ``printSum(arr[i][0], arr[i][1]);``    ``}` `    ``return` `0;``}`

## Java

 `// Java program to find the sum of all``// perfect cubes in the given range``import` `java.util.*;``import` `java.lang.*;``import` `java.io.*;` `/* Name of the class has to be "Main" only if the class is public. */``class` `GFG``{``    ``// Array to precompute the sum of cubes``    ``// from 1 to 100010 so that for every``    ``// query, the answer can be returned in O(1).``     ``public` `static` `int` `[]pref=``new` `int``[``100010``];``      ` `    ``// Function to check if a number is``    ``// a perfect Cube or not``    ``static` `int` `isPerfectCube(``int` `x)``    ``{``        ``// Find floating point value of``        ``// cube root of x.``        ``double` `cr = Math.round(Math.cbrt(x));``      ` `        ``// If cube root of x is cr``        ``// return the x, else 0``        ``if``(cr*cr*cr==(``double``)x) ``return` `x;``        ``return` `0``;``    ``}``      ` `    ``// Function to precompute the perfect``    ``// Cubes upto 100000.``    ``static` `void` `compute()``    ``{``        ``for` `(``int` `i = ``1``; i <= ``100000``; ++i) {``            ``pref[i] = pref[i - ``1``]+ isPerfectCube(i);``        ``}``    ``}``      ` `    ``// Function to print the sum for each query``    ``static` `void` `printSum(``int` `L, ``int` `R)``    ``{``        ``long` `sum = pref[R] - pref[L - ``1``];``        ``System.out.print(sum+``" "``);``    ``}``      ` `  ` `   ` `    ``// Driver code``    ``public` `static` `void` `main (String[] args)``    ``{``         ``// To calculate the precompute function``        ``compute();``      ` `        ``int` `Q = ``4``;``        ``int` `[][] arr = { { ``1``, ``10` `},``                                ``{ ``1``, ``100` `},``                                ``{ ``2``, ``25` `},``                                ``{ ``4``, ``50` `} };``      ` `        ``// Calling the printSum function``        ``// for every query``        ``for` `(``int` `i = ``0``; i < Q; i++) {``            ``printSum(arr[i][``0``], arr[i][``1``]);``        ``}``    ``}``}` `// This code is contributed by chitranayal`

## Python3

 `# Python3 program to find the sum of all``# perfect cubes in the given range` `# Array to precompute the sum of cubes``# from 1 to 100010 so that for every``# query, the answer can be returned in O(1).``pref ``=` `[``0``]``*``100010``;` `# Function to check if a number is``# a perfect Cube or not``def` `isPerfectCube(x) :` `    ``# Find floating point value of``    ``# cube root of x.``    ``cr ``=` `round``(x``*``*``(``1``/``3``));` `    ``# If cube root of x is cr``    ``# return the x, else 0``    ``rslt ``=` `x ``if` `(cr ``*` `cr ``*` `cr ``=``=` `x) ``else` `0``;``    ``return` `rslt;` `# Function to precompute the perfect``# Cubes upto 100000.``def` `compute() :``    ``for` `i ``in` `range``(``1``, ``100001``) :``        ``pref[i] ``=` `pref[i ``-` `1``] ``+` `isPerfectCube(i);` `# Function to print the sum for each query``def` `printSum(L, R) :` `    ``sum` `=` `pref[R] ``-` `pref[L ``-` `1``];``    ``print``(``sum` `,end``=` `" "``);` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:` `    ``# To calculate the precompute function``    ``compute();` `    ``Q ``=` `4``;``    ``arr``=` `[ [ ``1``, ``10` `],``            ``[ ``1``, ``100` `],``            ``[ ``2``, ``25` `],``            ``[ ``4``, ``50` `] ];` `    ``# Calling the printSum function``    ``# for every query``    ``for` `i ``in` `range``(Q) :``        ``printSum(arr[i][``0``], arr[i][``1``]);` `# This code is contributed by AnkitRai01`

## C#

 `// C# program to find the sum of all``// perfect cubes in the given range``using` `System;``      ` `class` `GFG {``// Array to precompute the sum of cubes``// from 1 to 100010 so that for every``// query, the answer can be returned in O(1).`` ``public` `static` `long` `[]pref=``new` `long``[100010];`` ` `// Function to check if a number is``// a perfect Cube or not``static` `long` `isPerfectCube(``long` `x)``{``    ``// Find floating point value of``    ``// cube root of x.``    ``double` `cr = Math.Round(MathF.Cbrt(x));`` ` `    ``// If cube root of x is cr``    ``// return the x, else 0``    ``if``(cr*cr*cr==(``double``)x) ``return` `x;``    ``return` `0;``}`` ` `// Function to precompute the perfect``// Cubes upto 100000.``static` `void` `compute()``{``    ``for` `(``long` `i = 1; i <= 100000; ++i) {``        ``pref[i] = pref[i - 1]``                  ``+ isPerfectCube(i);``    ``}``}`` ` `// Function to print the sum for each query``static` `void` `printSum(``int` `L, ``int` `R)``{``    ``long` `sum = pref[R] - pref[L - 1];``    ``Console.Write(sum+``" "``);``}`` ` `// Driver code``public` `static` `void` `Main()``  ``{``    ``// To calculate the precompute function``    ``compute();`` ` `    ``int` `Q = 4;``    ``int` `[,] arr = ``new` `int``[,]{ { 1, 10 },``                            ``{ 1, 100 },``                            ``{ 2, 25 },``                            ``{ 4, 50 } };`` ` `    ``// Calling the printSum function``    ``// for every query``    ``for` `(``int` `i = 0; i < Q; i++) {``        ``printSum(arr[i,0], arr[i,1]);``    ``}``  ``}``} ` `// This code is contributed by mohit kumar 29`

## Javascript

 ``
Output:
`9 100 8 35`

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