Dado un número, la tarea es verificar si un número es divisible por 4 o no. El número de entrada puede ser grande y puede que no sea posible almacenarlo incluso si usamos long long int.
Ejemplos:
Input : n = 1124 Output : Yes Input : n = 1234567589333862 Output : No Input : n = 363588395960667043875487 Output : No
Dado que el número de entrada puede ser muy grande, no podemos usar n % 4 para verificar si un número es divisible por 4 o no, especialmente en lenguajes como C/C++. La idea se basa en el siguiente hecho.
Un número es divisible por 4 si el número formado por sus dos últimas cifras es divisible por 4.
Ilustración:
For example, let us consider 76952 Number formed by last two digits = 52 Since 52 is divisible by 4, answer is YES.
¿Como funciona esto?
Let us consider 76952, we can write it as 76942 = 7*10000 + 6*1000 + 9*100 + 5*10 + 2 The proof is based on below observation: Remainder of 10i divided by 4 is 0 if i greater than or equal to two. Note than 100, 1000, ... etc lead to remainder 0 when divided by 4. So remainder of "7*10000 + 6*1000 + 9*100 + 5*10 + 2" divided by 4 is equivalent to remainder of following : 0 + 0 + 0 + 5*10 + 2 = 52 Therefore we can say that the whole number is divisible by 4 if 52 is divisible by 4.
A continuación se muestra la implementación de la idea anterior:
C++
// C++ program to find if a number is divisible by
// 4 or not
#include <bits/stdc++.h>
using namespace std;
// Function to find that number divisible by
// 4 or not
bool check(string str)
{
int n = str.length();
// Empty string
if (n == 0)
return false;
// If there is single digit
if (n == 1)
return ((str[0] - '0') % 4 == 0);
// If number formed by last two digits is
// divisible by 4.
int last = str[n - 1] - '0';
int second_last = str[n - 2] - '0';
return ((second_last * 10 + last) % 4 == 0);
}
// Driver code
int main()
{
string str = "76952";
// Function call
check(str) ? cout << "Yes" : cout << "No ";
return 0;
}
Java
// Java program to find if a number is
// divisible by 4 or not
class IsDivisible
{
// Function to find that number
// is divisible by 4 or not
static boolean check(String str)
{
int n = str.length();
// Empty string
if (n == 0)
return false;
// If there is single digit
if (n == 1)
return ((str.charAt(0) - '0') % 4 == 0);
// If number formed by last two digits is
// divisible by 4.
int last = str.charAt(n - 1) - '0';
int second_last = str.charAt(n - 2) - '0';
return ((second_last * 10 + last) % 4 == 0);
}
// Driver code
public static void main(String[] args)
{
String str = "76952";
// Function call
if (check(str))
System.out.println("Yes");
else
System.out.println("No");
}
}
Python3
# Python 3 program to find
# if a number is divisible
# by 4 or not
# Function to find that
# number divisible by
# 4 or not
def check(st):
n = len(st)
# Empty string
if (n == 0):
return False
# If there is single
# digit
if (n == 1):
return ((st[0] - '0') % 4 == 0)
# If number formed by
# last two digits is
# divisible by 4.
last = (int)(st[n - 1])
second_last = (int)(st[n - 2])
return ((second_last * 10 + last) % 4 == 0)
# Driver code
st = "76952"
# Function call
if(check(st)):
print("Yes")
else:
print("No ")
# This code is contributed by Nikita tiwari
C#
// C# program to find if a number is
// divisible by 4 or not
using System;
class GFG
{
// Function to find that number
// is divisible by 4 or not
static bool check(String str)
{
int n = str.Length;
// Empty string
if (n == 0)
return false;
// If there is single digit
if (n == 1)
return ((str[0] - '0') % 4 == 0);
// If number formed by last two
// digits is divisible by 4.
int last = str[n - 1] - '0';
int second_last = str[n - 2] - '0';
return ((second_last * 10 + last) % 4 == 0);
}
// Driver code
public static void Main()
{
String str = "76952";
// Function call
if (check(str))
Console.Write("Yes");
else
Console.Write("No");
}
}
// This code is Contributed by nitin mittal.
PHP
<?php
// PHP program to find if a
// number is divisible by
// 4 or not
// Function to find that
// number divisible by
// 4 or not
function check($str)
{
$n = strlen($str);
// Empty string
if ($n == 0)
return false;
// If there is single digit
if ($n == 1)
return (($str[0] - '0') % 4 == 0);
// If number formed by
// last two digits is
// divisible by 4.
$last = $str[$n - 1] - '0';
$second_last = $str[$n - 2] - '0';
return (($second_last * 10 + $last) % 4 == 0);
}
// Driver code
$str = "76952";
// Function call
$x = check($str)? "Yes" : "No";
echo($x);
// This code is contributed by Ajit.
?>
Javascript
//Javascript program to check whether a string is divisible by 4 or not
// function to check the divisibility
function check(str)
{
// checking the length for future reference
var n = str.length;
// if it is empty then directly returning false
if( n == 0)
{
return false;
}
if( n == 1)
{
return ((str[0] -'0') % 4 == 0);
}
var lastNumber = str[n-1] -'0';
var lastSecondNUmber = str[n-2] -'0';
return ((lastSecondNUmber * 10 + lastNumber) % 4 == 0);
}
// Driver code
var str="76952";
//checking the value by passing it into the function
// Function call
if(check(str)){
console.log("Yes");
}
else{
console.log("No");
}
Yes
Complejidad de tiempo : O (1), ya que no estamos usando ningún bucle para atravesar.
Espacio auxiliar: O(1), ya que no estamos utilizando ningún espacio adicional.
Método 2: comprobar que el número dado es divisible por 4 o no mediante el operador de división de módulo «%».
Python3
# Python code
# To check whether the given number is divisible by 4 or not
#input
n=1234567589333862
# the above input can also be given as n=input() -> taking input from user
# finding given number is divisible by 4 or not
if int(n)%4==0:
print("Yes")
else:
print("No")
# this code is contributed by gangarajula laxmi
C#
using System;
public class GFG{
static public void Main (){
// input
long n=1234567589333862;
// the above input can also be given as n=input() -> taking input from user
// finding given number is divisible by 7 or not
if (n % 4 == 0)
{
Console.Write("Yes");
}
else
{
Console.Write("No");
}
}
}
// This code is contributed by laxmigangarajula03
Javascript
<script>
// JavaScript code for the above approach
// To check whether the given number is divisible by 4 or not
//input
var n = 1234567589333862
// finding given number is divisible by 4 or not
if (n % 4 == 0)
document.write("Yes")
else
document.write("No")
// This code is contributed by Potta Lokesh
</script>
No
Complejidad de tiempo : O (1), ya que no estamos usando ningún bucle para atravesar.
Espacio auxiliar: O(1), ya que no estamos utilizando ningún espacio adicional.
Método 3: Uso de la función incorporada Atoi() en C++.
La función atoi() en C++ toma una string (que representa un número entero) como argumento y devuelve su valor de tipo int. Entonces, básicamente, la función se usa para convertir un argumento de string en un número entero.
Sintaxis:
int atoi(const char str)
Parámetros: la función acepta un parámetro str que se refiere al argumento de string que se necesita convertir en su equivalente entero.
Valor devuelto: si str es una entrada válida, la función devuelve el número entero equivalente para el número de string pasado. Si no tiene lugar una conversión válida, la función devuelve cero.
Implementación
C++
// C++ program to find if a number is divisible by
// 4 or not
#include <bits/stdc++.h>
using namespace std;
// Driver code
int main()
{
char str[] = "76952";
int n = (sizeof(str) / sizeof(char))-1;
char ch[2];
if (n >= 2) {
ch[0] = str[n - 2];
ch[1] = str[n - 1];
}
else if (n == 1) {
ch[0] = 0;
ch[1] = str[0];
}
int x;
x = atoi(ch);
if (!(x % 4)) {
cout << "YES";
}
else {
cout << "NO";
}
return 0;
}
// This code is contributed by Aarti_Rathi
YES
Complejidad de tiempo : O (1), ya que no estamos usando ningún bucle para atravesar.
Espacio auxiliar: O(1), ya que no estamos utilizando ningún espacio adicional.
Método 4: (usando la función de substring)
- Utilice la función de substring para obtener los dos últimos caracteres de la string.
- Convertir la string a entero
- Comprueba si es divisible por 4 o no, usando (número%4 == 0).
Este enfoque es aportado por Abhijeet Kumar .
A continuación se muestra la implementación del enfoque anterior:
C++
// C++ program to find if a number is divisible by
// 4 or not
#include <bits/stdc++.h>
using namespace std;
// Function to find that number divisible by
// 4 or not
bool check(string str)
{
// Get the length of the string
int n = str.length();
// Empty string
if (n == 0)
return false;
// stoi(string_variable) is used in C++
// to convert string to integer
// If there is single digit
if (n == 1)
return ((stoi(str)) % 4 == 0);
// getting last two characters using substring
str = str.substr(n - 2, 2);
// If number formed by last two digits is
// divisible by 4.
return ((stoi(str)) % 4 == 0);
}
// Driver code
int main()
{
string str = "76952";
// Function call
check(str) ? cout << "Yes" : cout << "No ";
return 0;
}
// This code is contributed by Abhijeet Kumar(abhijeet19403)
Java
// Java program to find if a number is
// divisible by 4 or not
class IsDivisible {
// Function to find that number
// is divisible by 4 or not
static boolean check(String str)
{
// Get the length of the string
int n = str.length();
// Empty string
if (n == 0)
return false;
// Integer.parseInt(string_variable) is used in Java
// to convert string to integer
// If there is single digit
if (n == 1)
return ((Integer.parseInt(str)) % 4 == 0);
// getting last two characters using substring
str = str.substring(n - 2);
// If number formed by last two digits is
// divisible by 4.
return ((Integer.parseInt(str)) % 4 == 0);
}
// Driver code
public static void main(String[] args)
{
String str = "76952";
// Function call
if (check(str))
System.out.println("Yes");
else
System.out.println("No");
}
}
// This code is contributed by Abhijeet Kumar(abhijeet19403)
Python3
# Python 3 program to find
# if a number is divisible
# by 4 or not
# Function to find that
# number divisible by
# 4 or not
def check(st):
n = len(st)
# Empty string
if (n == 0):
return False
# int(string_variable) is used in Python3
# to convert string to integer
# If there is single
# digit
if (n == 1):
return (int(st) % 4 == 0)
# slicing of strings is used in Python to function as substring
st = st[n-2:]
# If number formed by
# last two digits is
# divisible by 4.
return (int(st) % 4 == 0)
# Driver code
st = "76952"
# Function call
if(check(st)):
print("Yes")
else:
print("No ")
# This code is contributed by Abhijeet Kumar(abhijeet19403)
C#
// C# program to find if a number is
// divisible by 4 or not
using System;
class GFG
{
// Function to find that number
// is divisible by 4 or not
static bool check(String str)
{
int n = str.Length;
// Empty string
if (n == 0)
return false;
// int.Parse(string_variable) is used in C#
// to convert string to integer
// If there is single digit
if (n == 1)
return (int.Parse(str) % 4 == 0);
// getting last two characters using substring
str = str.Substring(n-2);
// If number formed by last two
// digits is divisible by 4.
return (int.Parse(str) % 4 == 0);
}
// Driver code
public static void Main()
{
String str = "76952";
// Function call
if (check(str))
Console.Write("Yes");
else
Console.Write("No");
}
}
// This code is Contributed by Abhijeet Kumar(abhijeet19403)
Javascript
//Javascript program to check whether a string is divisible by 4 or not
// function to check the divisibility
function check(str)
{
// checking the length for future reference
var n = str.length;
// if it is empty then directly returning false
if( n == 0)
{
return false;
}
// parseInt(string_variable) is used in Javascript
// to convert string to integer
if( n == 1)
{
return (parseInt(str) % 4 == 0);
}
// getting last two characters using substring
str = str.substring(n-2);
// If number formed by last two digits is
// divisible by 4.
return (parseInt(str) % 4 == 0);
}
// Driver code
var str="76952";
//checking the value by passing it into the function
// Function call
if(check(str)){
console.log("Yes");
}
else{
console.log("No");
}
// This code is contributed by Abhijeet Kumar(abhijeet19403)
Yes
Complejidad de tiempo: (1)
La función de substring toma el tiempo O(n), donde n es la longitud de la substring y como aquí n es igual a 2, la complejidad del tiempo es constante.
Espacio Auxiliar: O(1)
Como espacio adicional constante se utiliza.
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Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA