📜  立方和与前N个自然数之和的差

📅  最后修改于: 2021-05-05 02:15:02             🧑  作者: Mango

给定一个整数N,找到前N个自然数的立方和与前N个自然数的总和之间的绝对差。

Input: N = 3
Output: 30
Sum of first three numbers is 3 + 2 + 1 = 6
Sum of Cube of first three numbers is = 1 + 8 + 27 = 36
Absolute difference = 36 - 6 = 30

Input: N = 5
Output: 210

方法:

  1. 前N个自然数的立方的总和,使用以下公式:
    (N ( N + 1 ) / 2) ^ 2
  2. 前N个数字的总和,使用以下公式:
    (N ( N + 1 ) / 2)
  3. 两者之和的绝对差为
    S(S-1)
    在哪里
    S = (N ( N + 1 ) / 2)

下面是上述方法的实现:

C++
// C++ program to find the difference
// between the sum of the cubes of the
// first N natural numbers and
// the sum of the first N natural number
 
#include 
using namespace std;
 
int difference(int n)
{
 
    int S, res;
 
    // Sum of first n natural numbers
    S = (n * (n + 1)) / 2;
 
    // Find the required difference
    res = S * (S - 1);
 
    return res;
}
 
// Driver Code
int main()
{
    int n = 5;
    cout << difference(n);
 
    return 0;
}


Java
// Java program to find the difference
// between the sum of the cubes of the
// first N natural numbers and
// the sum of the first N natural number
 
class GFG
{
 
static int difference(int n)
{
 
    int S, res;
 
    // Sum of first n natural numbers
    S = (n * (n + 1)) / 2;
 
    // Find the required difference
    res = S * (S - 1);
 
    return res;
}
 
// Driver Code
public static void main(String[] args)
{
    int n = 5;
    System.out.print(difference(n));
}
}
 
// This code is contributed by 29AjayKumar


Python3
# Python3 program to find the difference
# between the sum of the cubes of the
# first N natural numbers and
# the sum of the first N natural number
def difference(n) :
 
    # Sum of first n natural numbers
    S = (n * (n + 1)) // 2;
 
    # Find the required difference
    res = S * (S - 1);
 
    return res;
 
# Driver Code
if __name__ == "__main__" :
 
    n = 5;
    print(difference(n));
     
# This code is contributed by AnkitRai01


C#
// C# program to find the difference
// between the sum of the cubes of the
// first N natural numbers and
// the sum of the first N natural number
using System;
 
class GFG
{
static int difference(int n)
{
    int S, res;
 
    // Sum of first n natural numbers
    S = (n * (n + 1)) / 2;
 
    // Find the required difference
    res = S * (S - 1);
 
    return res;
}
 
// Driver Code
static public void Main ()
{
    int n = 5;
    Console.Write(difference(n));
}
}
 
// This code is contributed by ajit


Javascript


输出:
210