LeetCode in Kotlin
1399. Count Largest Group
Easy
You are given an integer n.
Each number from 1 to n is grouped according to the sum of its digits.
Return the number of groups that 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.
Constraints:
1 <= n <= 104
Solution
@Suppress("NAME_SHADOWING")
class Solution {
fun countLargestGroup(n: Int): Int {
var largest = 0
val map = IntArray(37)
var sumOfDigit = 0
for (i in 1..n) {
if (i % 10 == 0) {
// reset and start a new sum
sumOfDigit = getSumOfDigits(i)
} else {
sumOfDigit++
}
val `val` = ++map[sumOfDigit]
largest = if (`val` > largest) `val` else largest
}
return countLargestGroup(largest, map)
}
private fun countLargestGroup(largest: Int, arr: IntArray): Int {
var count = 0
for (`val` in arr) {
if (`val` == largest) {
count++
}
}
return count
}
private fun getSumOfDigits(num: Int): Int {
var num = num
var sum = 0
while (num > 0) {
sum += num % 10
num /= 10
}
return sum
}
}