计算主要因子分别为2和3的范围内的数字

给定两个正整数L和R ，任务是计算素数仅为2和3的范围[L，R]中的元素。

例子：

Input: L = 1, R = 10
Output: 6
2 = 2
3 = 3
4 = 2 * 2
6 = 2 * 3
8 = 2 * 2 * 2
9 = 3 * 3

Input: L = 100, R = 200
Output: 5

方法：从L到R以及每个num元素开始循环：

• num被2整除时，将其除以2 。
• num被3整除时，将其除以3 。
• 如果num = 1，则递增计数，因为num仅将2和3作为其主要因子。

最后打印计数。

下面是上述方法的实现：

C++

// C++ program to count the numbers within a range
// whose prime factors are only 2 and 3
#include 
using namespace std;
  
// Function to count the number within a range
// whose prime factors are only 2 and 3
int findTwoThreePrime(int l, int r)
{
    // Start with 2 so that 1 doesn't get counted
    if (l == 1)
        l++;
  
    int count = 0;
  
    for (int i = l; i <= r; i++) {
        int num = i;
  
        // While num is divisible by 2, divide it by 2
        while (num % 2 == 0)
            num /= 2;
  
        // While num is divisible by 3, divide it by 3
        while (num % 3 == 0)
            num /= 3;
  
        // If num got reduced to 1 then it has
        // only 2 and 3 as prime factors
        if (num == 1)
            count++;
    }
  
    return count;
}
  
// Driver code
int main()
{
    int l = 1, r = 10;
    cout << findTwoThreePrime(l, r);
    return 0;
}

Java

//Java program to count the numbers within a range 
// whose prime factors are only 2 and 3 
  
import java.io.*;
  
class GFG {
      
// Function to count the number within a range 
// whose prime factors are only 2 and 3 
static int findTwoThreePrime(int l, int r) 
{ 
    // Start with 2 so that 1 doesn't get counted 
    if (l == 1) 
        l++; 
  
    int count = 0; 
  
    for (int i = l; i <= r; i++) { 
        int num = i; 
  
        // While num is divisible by 2, divide it by 2 
        while (num % 2 == 0) 
            num /= 2; 
  
        // While num is divisible by 3, divide it by 3 
        while (num % 3 == 0) 
            num /= 3; 
  
        // If num got reduced to 1 then it has 
        // only 2 and 3 as prime factors 
        if (num == 1) 
            count++; 
    } 
  
    return count; 
} 
  
// Driver code 
    public static void main (String[] args) {
  
        int l = 1, r = 10; 
        System.out.println (findTwoThreePrime(l, r)); 
    }
//This code is contributed by ajit    
}

Python3

# Python3 program to count the numbers 
# within a range whose prime factors 
# are only 2 and 3
  
# Function to count the number within 
# a range whose prime factors are only 
# 2 and 3
def findTwoThreePrime(l, r) :
  
    # Start with 2 so that 1 
    # doesn't get counted
    if (l == 1) :
        l += 1
  
    count = 0
  
    for i in range(l, r + 1) :
        num = i
  
        # While num is divisible by 2, 
        # divide it by 2
        while (num % 2 == 0) :
            num //= 2;
  
        # While num is divisible by 3, 
        # divide it by 3
        while (num % 3 == 0) :
            num //= 3
  
        # If num got reduced to 1 then it has
        # only 2 and 3 as prime factors
        if (num == 1) :
            count += 1
  
    return count
  
# Driver code
if __name__ == "__main__" :
  
    l = 1
    r = 10
      
    print(findTwoThreePrime(l, r))
      
# This code is contributed by Ryuga

C#

// C# program to count the numbers 
// within a range whose prime factors 
// are only 2 and 3 
using System;
  
class GFG
{
          
// Function to count the number 
// within a range whose prime
// factors are only 2 and 3 
static int findTwoThreePrime(int l, int r) 
{ 
    // Start with 2 so that 1 
    // doesn't get counted 
    if (l == 1) 
        l++; 
  
    int count = 0; 
  
    for (int i = l; i <= r; i++) 
    { 
        int num = i; 
  
        // While num is divisible by 2,
        // divide it by 2 
        while (num % 2 == 0) 
            num /= 2; 
  
        // While num is divisible by 3, 
        // divide it by 3 
        while (num % 3 == 0) 
            num /= 3; 
  
        // If num got reduced to 1 then it  
        // has only 2 and 3 as prime factors 
        if (num == 1) 
            count++; 
    } 
    return count; 
} 
  
// Driver code 
static public void Main ()
{
    int l = 1, r = 10; 
    Console.WriteLine(findTwoThreePrime(l, r)); 
}
}
  
// This code is contributed by akt_mit

输出：

6