LeetCode in Kotlin

313. Super Ugly Number

Medium

A super ugly number is a positive integer whose prime factors are in the array primes.

Given an integer n and an array of integers primes, return the nth super ugly number.

The nth super ugly number is guaranteed to fit in a 32-bit signed integer.

Example 1:

Input: n = 12, primes = [2,7,13,19]

Output: 32

Explanation: [1,2,4,7,8,13,14,16,19,26,28,32] is the sequence of the first 12 super ugly numbers given primes = [2,7,13,19].

Example 2:

Input: n = 1, primes = [2,3,5]

Output: 1

Explanation: 1 has no prime factors, therefore all of its prime factors are in the array primes = [2,3,5].

Constraints:

• 1 <= n <= 105
• 1 <= primes.length <= 100
• 2 <= primes[i] <= 1000
• primes[i] is guaranteed to be a prime number.
• All the values of primes are unique and sorted in ascending order.

Solution

class Solution {
    fun nthSuperUglyNumber(n: Int, primes: IntArray): Int {
        val primes1 = LongArray(primes.size)
        for (i in primes.indices) {
            primes1[i] = primes[i].toLong()
        }
        val index = IntArray(primes.size)
        val n1 = LongArray(n)
        n1[0] = 1L
        for (i in 1 until n) {
            var min = Long.MAX_VALUE
            for (l in primes1) {
                min = Math.min(min, l)
            }
            n1[i] = min
            for (j in primes1.indices) {
                if (min == primes1[j]) {
                    primes1[j] = primes[j] * n1[++index[j]]
                }
            }
        }
        return n1[n - 1].toInt()
    }
}

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