LeetCode in Kotlin

811. Subdomain Visit Count

Medium

A website domain "discuss.leetcode.com" consists of various subdomains. At the top level, we have "com", at the next level, we have "leetcode.com" and at the lowest level, "discuss.leetcode.com". When we visit a domain like "discuss.leetcode.com", we will also visit the parent domains "leetcode.com" and "com" implicitly.

A count-paired domain is a domain that has one of the two formats "rep d1.d2.d3" or "rep d1.d2" where rep is the number of visits to the domain and d1.d2.d3 is the domain itself.

• For example, "9001 discuss.leetcode.com" is a count-paired domain that indicates that discuss.leetcode.com was visited 9001 times.

Given an array of count-paired domains cpdomains, return an array of the count-paired domains of each subdomain in the input. You may return the answer in any order.

Example 1:

Input: cpdomains = [“9001 discuss.leetcode.com”]

Output: [“9001 leetcode.com”,”9001 discuss.leetcode.com”,”9001 com”]

Explanation: We only have one website domain: “discuss.leetcode.com”. As discussed above, the subdomain “leetcode.com” and “com” will also be visited. So they will all be visited 9001 times.

Example 2:

Input: cpdomains = [“900 google.mail.com”, “50 yahoo.com”, “1 intel.mail.com”, “5 wiki.org”]

Output: [“901 mail.com”,”50 yahoo.com”,”900 google.mail.com”,”5 wiki.org”,”5 org”,”1 intel.mail.com”,”951 com”]

Explanation: We will visit “google.mail.com” 900 times, “yahoo.com” 50 times, “intel.mail.com” once and “wiki.org” 5 times. For the subdomains, we will visit “mail.com” 900 + 1 = 901 times, “com” 900 + 50 + 1 = 951 times, and “org” 5 times.

Constraints:

• 1 <= cpdomain.length <= 100
• 1 <= cpdomain[i].length <= 100
• cpdomain[i] follows either the "repi d1i.d2i.d3i" format or the "repi d1i.d2i" format.
• repi is an integer in the range [1, 104].
• d1i, d2i, and d3i consist of lowercase English letters.

Solution

class Solution {
    fun subdomainVisits(d: Array<String>): List<String> {
        val fmap: MutableMap<String, Int> = HashMap()
        for (s in d) {
            var rep = 0
            var i: Int = 0
            while (i < s.length) {
                val c = s[i]
                rep = if (c in '0'..'9') {
                    rep * 10 + (c.code - '0'.code)
                } else {
                    break
                }
                i++
            }
            val str = s.substring(i + 1)
            seperate(rep, str, fmap)
        }
        val res: MutableList<String> = ArrayList()
        for (entry in fmap.entries.iterator()) {
            var comp = ""
            comp += entry.value
            comp += " "
            comp += entry.key
            res.add(comp)
        }
        return res
    }

    private fun seperate(rep: Int, s: String, fmap: MutableMap<String, Int>) {
        var i = s.length - 1
        while (i >= 0) {
            while (i >= 0 && s[i] != '.') {
                i--
            }
            val toHash: String = s.substring(i + 1)
            fmap[toHash] = fmap.getOrDefault(toHash, 0) + rep
            i--
        }
    }
}

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