Hay N número de personas en una fiesta. Encuentre el número total de apretones de manos tales que una persona pueda dar un apretón de manos solo una vez.
Ejemplos:
Input : 5 Output : 10 Input : 9 Output : 36
Podemos ver una naturaleza recursiva en el problema.
// n-th person has (n-1) choices and after // n-th person chooses a person, problem // recurs for n-1. handshake(n) = (n-1) + handshake(n-1) // Base case handshake(0) = 0
A continuación se muestra la implementación de la fórmula recursiva anterior.
C++
// Recursive C++ program to count total number of handshakes
// when a person can shake hand with only one.
#include <bits/stdc++.h>
using namespace std;
// Function to find all possible handshakes
int handshake(int n)
{
// When n becomes 0 that means all the persons have done
// handshake with other
if (n == 0)
return 0;
else
return (n - 1) + handshake(n - 1);
}
// Driver code
int main()
{
int n = 9;
cout << " " << handshake(n);
return 0;
}
// This code is contributed by Aditya Kumar (adityakumar129)
C
// Recursive C program to count total number of handshakes
// when a person can shake hand with only one.
#include <stdio.h>
// function to find all possible handshakes
int handshake(int n)
{
// when n becomes 0 that means all the persons have done
// handshake with other
if (n == 0)
return 0;
else
return (n - 1) + handshake(n - 1);
}
int main()
{
int n = 9;
printf("%d", handshake(n));
return 0;
}
// This code is contributed by Aditya Kumar (adityakumar129)
Java
// Recursive Java program to count total number of
// handshakes when a person can shake hand with only one.
import java.io.*;
class GFG {
// function to find all possible handshakes
static int handshake(int n)
{
// when n becomes 0 that means all the persons have
// done handshake with other
if (n == 0)
return 0;
else
return (n - 1) + handshake(n - 1);
}
// Driver Code
public static void main(String[] args)
{
int n = 9;
System.out.print(handshake(n));
}
}
// This code is contributed by Aditya Kumar (adityakumar129)
Python3
# Recursive Python program # to count total number of # handshakes when a person # can shake hand with only one. # function to find all # possible handshakes def handshake(n): # when n becomes 0 that means # all the persons have done # handshake with other if (n == 0): return 0 else: return (n - 1) + handshake(n - 1) # Driver Code n = 9 print(handshake(n)) # This code is contributed # by Shivi_Aggarwal
C#
// Recursive C# program to
// count total number of
// handshakes when a person
// can shake hand with only one.
using System;
class GFG
{
// function to find all
// possible handshakes
static int handshake(int n)
{
// when n becomes 0 that
// means all the persons
// have done handshake
// with other
if (n == 0)
return 0;
else
return (n - 1) + handshake(n - 1);
}
// Driver Code
public static void Main (String []args)
{
int n = 9;
Console.WriteLine(handshake(n));
}
}
// This code is contributed
// by Arnab Kundu
PHP
<?php
// Recursive PHP program to
// count total number of
// handshakes when a person
// can shake hand with only one.
// function to find all
// possible handshakes
function handshake($n)
{
// when n becomes 0 that means
// all the persons have done
// handshake with other
if ($n == 0)
return 0;
else
return ($n - 1) + handshake($n - 1);
}
// Driver Code
$n = 9;
echo(handshake($n));
// This code is contributed
// by Shivi_Aggarwal
?>
Javascript
<script>
// Recursive JavaScript program to
// count total number of
// handshakes when a person
// can shake hand with only one.
// function to find all
// possible handshakes
function handshake(n) {
// when n becomes 0 that
// means all the persons
// have done handshake
// with other
if (n === 0)
return 0;
else
return n - 1 + handshake(n - 1);
}
// Driver Code
var n = 9;
document.write(handshake(n));
</script>
Producción:
36
Podemos llegar a una fórmula directa expandiendo la recursividad.
handshake(n) = (n-1) + handshake(n-1)
= (n-1) + (n-2) + handshake(n-2)
= (n-1) + (n-2) + .... 1 + 0
= n * (n - 1)/2
C++
// Recursive CPP program to count total number of handshakes
// when a person can shake hand with only one.
#include <bits/stdc++.h>
using namespace std;
// function to find all possible handshakes
int handshake(int n) { return n * (n - 1) / 2; }
int main()
{
int n = 9;
cout << handshake(n) << endl;
return 0;
}
// This code is contributed by Aditya Kumar (adityakumar129)
C
// Recursive CPP program to count total number of handshakes
// when a person can shake hand with only one.
#include <stdio.h>
// function to find all possible handshakes
int handshake(int n) { return n * (n - 1) / 2; }
int main()
{
int n = 9;
printf("%d", handshake(n));
return 0;
}
// This code is contributed by Aditya Kumar (adityakumar129)
Java
// Recursive Java program to count total number of
// handshakes when a person can shake hand with only one.
class GFG {
// function to find all possible handshakes
static int handshake(int n) { return n * (n - 1) / 2; }
// Driver code
public static void main(String args[])
{
int n = 9;
System.out.println(handshake(n));
}
}
// This code is contributed by Aditya Kumar (adityakumar129)
Python3
# Recursive Python program # to count total number of # handshakes when a person # can shake hand with only one. # function to find all # possible handshakes def handshake(n): return int(n * (n - 1) / 2) # Driver Code n = 9 print(handshake(n)) # This code is contributed # by Shivi_Aggarwal
C#
// Recursive C# program to
// count total number of
// handshakes when a person
// can shake hand with only one.
using System;
class GFG
{
// function to find all
// possible handshakes
static int handshake(int n)
{
return n * (n - 1) / 2;
}
// Driver code
static public void Main ()
{
int n = 9;
Console.WriteLine(handshake(n));
}
}
// This code is contributed by Sachin
PHP
<?php
// Recursive PHP program to
// count total number of
// handshakes when a person
// can shake hand with only one.
// function to find all
// possible handshakes
function handshake($n)
{
return $n * ($n - 1) / 2;
}
// Driver Code
$n = 9;
echo(handshake($n));
// This code is contributed
// by Shivi_Aggarwal
?>
Javascript
<script>
// Recursive Javascript program to
// count total number of
// handshakes when a person
// can shake hand with only one.
// Function to find all
// possible handshakes
function handshake(n)
{
return n * parseInt((n - 1) / 2, 10);
}
// Driver code
let n = 9;
document.write(handshake(n));
// This code is contributed by rameshtravel07
</script>
Producción:
36
Publicación traducida automáticamente
Artículo escrito por Mohd_Saliem y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA