LeetCode in Kotlin

2283. Check if Number Has Equal Digit Count and Digit Value

Easy

You are given a 0-indexed string num of length n consisting of digits.

Return true if for every index i in the range 0 <= i < n, the digit i occurs num[i] times in num, otherwise return false.

Example 1:

Input: num = “1210”

Output: true

Explanation:

num[0] = ‘1’. The digit 0 occurs once in num.

num[1] = ‘2’. The digit 1 occurs twice in num.

num[2] = ‘1’. The digit 2 occurs once in num.

num[3] = ‘0’. The digit 3 occurs zero times in num.

The condition holds true for every index in “1210”, so return true.

Example 2:

Input: num = “030”

Output: false

Explanation:

num[0] = ‘0’. The digit 0 should occur zero times, but actually occurs twice in num.

num[1] = ‘3’. The digit 1 should occur three times, but actually occurs zero times in num.

num[2] = ‘0’. The digit 2 occurs zero times in num.

The indices 0 and 1 both violate the condition, so return false.

Constraints:

Solution

class Solution {
    fun digitCount(num: String): Boolean {
        val cnt = IntArray(11)
        val arr = num.toCharArray()
        for (d in arr) {
            ++cnt[d.code - '0'.code]
        }
        for (i in arr.indices) {
            if (cnt[i] != arr[i].code - '0'.code) {
                return false
            }
        }
        return true
    }
}