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Check if frequency of each digit is less than the digit

Last Updated : 13 Sep, 2023
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Given an integer n, the task is to check if frequency of each digit of the number is less than or equal to digit itself. 
Examples: 
 

Input : 51241
Output : False

Input : 1425243
Output : True


 


Naive Approach: Start from 0 and count the frequency for every digit upto 9, if at any place frequency is more than the digit value then return false, else return true.
 

C++ 
// A C++ program to validate a number
#include<bits/stdc++.h>
using namespace std;

// Function to validate number (Check if
// frequency of a digit is less than the
// digit itself or not)
bool validate(long long int n)
{
    for (int i=0; i<10; i++)
    {
        long long int temp = n; 
        int count = 0;
        while (temp)
        {
            // If current digit of temp is
            // same as i
            if (temp % 10 == i)
                count++;

            // if frequency is greater than 
            // digit value, return false
            if (count > i)
                return false;

            temp /= 10;
        }
    }
    return true;
}

// driver program
int main()
{
    long long int n = 1552793;
    if (validate(n))
        cout << "True";
    else
        cout << "False";
    return 0;
}
Java 
// Java program to validate a number
import java .io.*;

public class GFG {

// Function to validate number (Check if
// frequency of a digit is less than the
// digit itself or not)
static boolean validate(long n)
{
    for (int i = 0; i < 10; i++)
    {
        long temp = n; 
        int count = 0;
        while (temp > 0)
        {
            // If current digit of 
            // temp is same as i
            if (temp % 10 == i)
                count++;

            // if frequency is greater than 
            // digit value, return false
            if (count > i)
                return false;

            temp /= 10;
        }
    }
    return true;
}

    // Driver Code
    static public void main (String[] args)
    {
            long n = 1552793;
        if (validate(n))
            System.out.println("True");
        else
            System.out.println("False");
    }
}

// This code is contributed by vt_m.
Python3 
# Python3 program to validate a number

# Function to validate number (Check if 
# frequency of a digit is less than the
# digit itself or not)
def validate(n):

    for i in range(10):
        temp = n; 
        count = 0;
        while (temp):
            
            # If current digit of temp is 
            # same as i
            if (temp % 10 == i):
                count+=1;

            # if frequency is greater than 
            # digit value, return false
            if (count > i):
                return -1;

            temp //= 10;

    return 1;

# Driver Code
n = 1552793;
geek = "True" if validate(n) else "False";
print(geek);

# This code is contributed by mits
C# 
// C# program to validate a number
using System;

public class GFG {

// Function to validate number (Check if
// frequency of a digit is less than the
// digit itself or not)
static bool validate(long n)
{
    for (int i = 0; i < 10; i++)
    {
        long temp = n; 
        int count = 0;
        while (temp > 0)
        {
            // If current digit of 
            // temp is same as i
            if (temp % 10 == i)
                count++;

            // if frequency is greater than 
            // digit value, return false
            if (count > i)
                return false;

            temp /= 10;
        }
    }
    return true;
}

    // Driver Code
    static public void Main(String[] args)
    {
            long n = 1552793;
        if (validate(n))
            Console.WriteLine("True");
        else
            Console.WriteLine("False");
    }
}

// This code is contributed by vt_m.
PHP 
<?php
// PHP program to validate a number

// Function to validate number
// (Check if frequency of a
// digit is less than the
// digit itself or not)
function validate($n)
{
    for ($i = 0; $i < 10; $i++)
    {
        $temp = $n; 
        $count = 0;
        while ($temp)
        {
            
            // If current digit 
            // of temp is same 
            // as i
            if ($temp % 10 == $i)
                $count++;

            // if frequency is
            // greater than digit 
            // value, return false
            if ($count > $i)
                return -1;

            $temp /= 10;
        }
    }
    return 1;
}

    // Driver Code
    $n = 1552793;
    $geek = validate($n) ?"True" :"False";
    echo($geek);

// This code is contributed by Ajit
?>
JavaScript 
<script>

// JavaScript program for the above approach

// Function to validate number (Check if
// frequency of a digit is less than the
// digit itself or not)
function  validate(n)
{
    for (let i = 0; i < 10; i++)
    {
        let temp = n; 
        let count = 0;
        while (temp > 0)
        {
            // If current digit of 
            // temp is same as i
            if (temp % 10 == i)
                count++;

            // if frequency is greater than 
            // digit value, return false
            if (count > i)
                return false;

            temp /= 10;
        }
    }
    return true;
}

// Driver Code
    
    let n = 1552793;
    if (validate(n))
       document.write("True");
    else
      document.write("False");

// This code is contributed by susmitakundugoaldanga.
</script>

Output: 
 

True

Time Complexity: O(10 * log10n), where n represents the given integer.
Auxiliary Space: O(1), no extra space is required, so it is a constant.


Efficient Approach: is to store the frequency of each digit and if at any place frequency is more than the digit value then return false, else return true.
 

C++ 
// A C++ program to validate a number
#include<bits/stdc++.h>
using namespace std;

// Function to validate number (Check if 
// frequency of a digit is less than the 
// digit itself or not)
bool validate(long long int n)
{
    int count[10] = {0};  
    while (n)
    {
        // calculate frequency of each digit
        int r = n % 10;

        // If count is already r, then
        // incrementing it would invalidate, 
        // hence we return false.
        if (count[r] == r)
           return false;  

        count[r]++;
        n /= 10;
    }

    return true;
}

// driver program
int main()
{
    long long int n = 1552793;
    if (validate(n))
        cout << "True";
    else
        cout << "False";
    return 0;
}
Java 
// A Java program to
// validate a number
import java.io.*;

class GFG 
{
    
// Function to validate
// number (Check if frequency 
// of a digit is less than 
// the digit itself or not)
static boolean validate(long n)
{
    int count[] = new int[10] ; 
    while (n > 0)
    {
        // calculate frequency 
        // of each digit
        int r = (int)n % 10;

        // If count is already r, 
        // then incrementing it 
        // would invalidate, 
        // hence we return false.
        if (count[r] == r)
        return false; 

        count[r]++;
        n /= 10;
    }

    return true;
}

// Driver Code
public static void main (String[] args)
{
    long n = 1552793;
    if (validate(n))
        System.out.println("True");
    else
        System.out.println("False");
}
}

// This code is contributed by ajit
Python3 
# A Python3 program to validate a number
import math as mt

# Function to validate number (Check if 
# frequency of a digit is less than the 
# digit itself or not)
def validate(n):

    count = [0 for i in range(10)] 
    while (n > 0):
    
        # calculate frequency of each digit
        r = n % 10

        # If count is already r, then
        # incrementing it would invalidate, 
        # hence we return false.
        if (count[r] == r):
            return False

        count[r] += 1
        n = n // 10
    
    return True

# Driver Code
n = 1552793
if (validate(n)):
    print("True")
else:
    print("False")

# This code is contributed by 
# Mohit kumar 29
C# 
// A C# program to validate a number 
using System;

class GFG
{
// Function to validate number 
// (Check if frequency of a digit is 
// less than the digit itself or not) 
static bool validate(long n) 
{ 
    int []count = new int[10] ; 
    while (n > 0) 
    { 
        // calculate frequency 
        // of each digit 
        int r = (int)n % 10; 

        // If count is already r, then  
        // incrementing it would invalidate, 
        // hence we return false. 
        if (count[r] == r) 
        return false; 

        count[r]++; 
        n /= 10; 
    } 

    return true; 
} 

// Driver Code 
static public void Main ()
{
    long n = 1552793; 
    if (validate(n)) 
        Console.WriteLine("True"); 
    else
        Console.WriteLine("False"); 
} 
} 

// This code is contributed by jit_t
PHP 
<?php
// A PHP program to validate a number

// Function to validate number (Check if 
// frequency of a digit is less than the 
// digit itself or not)
function validate($n)
{
    $count=array(10);
    while ($n)
    {
        // calculate frequency of each digit
        $r = $n % 10;

        // If count is already r, then
        // incrementing it would invalidate, 
        // hence we return false.
        if (($count[$r] == $r))
        {
            return false; 
        }

        $count[$r] = $count[$r] + 1;
        $n = $n / 10;
    }

    return true;
}

// Driver Code
    $n = 1552793;
    $geek = validate($n) ?"True" :"False";
    echo($geek);
?>
JavaScript 
<script>

// A JavaScript program to validate a number

// Function to validate number (Check if
// frequency of a digit is less than the
// digit itself or not)
function validate(n)
{
    let count = new Uint8Array(10);
    while (n)
    {
        // calculate frequency of each digit
        let r = n % 10;

        // If count is already r, then
        // incrementing it would invalidate,
        // hence we return false.
        if (count[r] == r)
        return false;

        count[r]++;
        n = Math.floor(n / 10);
    }

    return true;
}

// driver program

    let n = 1552793;
    if (validate(n))
        document.write( "True");
    else
        document.write("False");


// This code is contributed by Surbhi Tyagi.

</script>

Output: 

True

Time Complexity: O(log10n), where n represents the given integer.
Auxiliary Space: O(10), no extra space is required, so it is a constant.


 


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