CountLargestGroup1399.kt

package easy

/*
Given an integer n. Each number from 1 to n is grouped according to the sum of its digits.

Return how many groups have the largest size.
Example 1:

Input: n = 13
Output: 4
Explanation: There are 9 groups in total, they are grouped according sum of its digits of numbers from 1 to 13:
[1,10], [2,11], [3,12], [4,13], [5], [6], [7], [8], [9]. There are 4 groups with largest size.
Example 2:

Input: n = 2
Output: 2
Explanation: There are 2 groups [1], [2] of size 1.
Example 3:

Input: n = 15
Output: 6
Example 4:

Input: n = 24
Output: 5
 */
fun countLargestGroup(n: Int): Int {
    val map =HashMap<Int,Int>()
    for(i in 1..n)
    {
        if(i in 1..9)
            map[i]=1
        else
        {
            var result=0
            var num=i
            while(num!=0)
            {
                result+=num%10
                num/=10
            }
            map[result]=(map[result]?:0).plus(1)
        }
    }
    var max=Int.MIN_VALUE
    var count=0
    map.entries.forEach {entry->
        if(entry.value>max)
        {
            max=entry.value
        }
    }
    map.entries.forEach {entry->
        if(entry.value==max)
        {
            count++
        }
    }
    return count
}