Smallest number by rearranging digits of a given number - GeeksforGeeks

Smallest number by rearranging digits of a given number - GeeksforGeeks
Find the Smallest number (Not leading Zeros) which can be obtained by rearranging the digits of given number.

1. Count the frequency of each digit in the number.
2. Place the smallest digit (except 0) at the left most of required number.
   and decrement the frequency of that digit by 1.
3. Place all remaining digits in ascending order from left to right.

int smallest(int num)

{

    // initialize frequency of each digit to Zero

    int freq[10] = {0};

 

    // count frequency of each digit in the number

    while (num)

    {

        int d = num % 10; // extract last digit

        freq[d]++; // increment counting

        num = num / 10; //remove last digit

    }

 

    // Set the LEFTMOST digit to minimum expect 0

    int result = 0;

    for (int i = 1 ; i <= 9 ; i++)

    {

        if (freq[i])

        {

            result = i;

            freq[i]--;

            break;

        }

    }

 

    // arrange all remaining digits

    // in ascending order

    for (int i = 0 ; i <= 9 ; i++)

        while (freq[i]--)

            result = result * 10 + i;

 

    return result;

}

Read full article from Smallest number by rearranging digits of a given number - GeeksforGeeks