Sea a n una secuencia de números, que está definida por la relación de recurrencia a 1 =1 y a n+1 /a n =2 n . La tarea es encontrar el valor de log 2 (a n ) para un n dado .
Ejemplos:
Input: 5 Output: 10 Explanation: log2(an) = (n * (n - 1)) / 2 = (5*(5-1))/2 = 10 Input: 100 Output: 4950
, We multiply all of the above in order to reach
Since . Then
.
Substituting n+1 for n:
So,
Below is the implementation of above approach.
C++
// C++ program to find nth term of // a given recurrence relation #include <bits/stdc++.h> using namespace std; // function to return required value int sum(int n) { // Get the answer int ans = (n * (n - 1)) / 2; // Return the answer return ans; } // Driver program int main() { // Get the value of n int n = 5; // function call to print result cout << sum(n); return 0; }
Java
// Java program to find nth term // of a given recurrence relation import java.util.*; class solution { static int sum(int n) { // Get the answer int ans = (n * (n - 1)) / 2; // Return the answer return ans; } // Driver code public static void main(String arr[]) { // Get the value of n int n = 5; // function call to print result System.out.println(sum(n)); } } //This code is contributed byte //Surendra_Gangwar
Python3
# Python3 program to find nth # term of a given recurrence # relation # function to return # required value def sum(n): # Get the answer ans = (n * (n - 1)) / 2; # Return the answer return ans # Driver Code # Get the value of n n = 5 # function call to prresult print(int(sum(n))) # This code is contributed by Raj
C#
// C# program to find nth term // of a given recurrence relation using System; class GFG { static int sum(int n) { // Get the answer int ans = (n * (n - 1)) / 2; // Return the answer return ans; } // Driver code public static void Main() { // Get the value of n int n = 5; // function call to print result Console.WriteLine(sum(n)); } } // This code is contributed byte // inder_verma
PHP
<?php // PHP program to find nth term of // a given recurrence relation // function to return required value function sum($n) { // Get the answer $ans = ($n * ($n - 1)) / 2; // Return the answer return $ans; } // Driver Code // Get the value of n $n = 5; // function call to print result echo sum($n); // This code is contributed by // inder_verma ?>
Javascript
<script> // Javascript program to find nth term of // a given recurrence relation // function to return required value function sum(n) { // Get the answer let ans = parseInt((n * (n - 1)) / 2); // Return the answer return ans; } // Driver program // Get the value of n let n = 5; // function call to print result document.write(sum(n)); // This code is contributed by subham348. </script>
Producción:
10
Complejidad de tiempo: O(1)
Publicación traducida automáticamente
Artículo escrito por Sanjit_Prasad y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA