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LESSON 193 OF 414 · NESTED LOOPS

Top K Brands V4 - Top K in Kotlin

Practice

Show the top k brands by rating. This is v3's search, repeated k times: find the best brand, mark it as taken, then search again among the brands that are not taken yet, until you have k brands in rank order.

You start with:

        val brands = arrayOf("TechPro", "MegaCorp", "Quantum", "NeoByte", "Zenith")
        val ratings = intArrayOf(4, 5, 3, 5, 4)
        val k = 3

Build:

1. MegaCorp (5)
2. NeoByte (5)
3. TechPro (4)

Rules:

  • Repeat v3's search k times. Each round looks only at brands that are not taken yet and picks the one with the highest rating, then marks it as taken (one true/false flag per brand).
  • Ties go to the brand listed first: keep the first brand you find and replace it only on a strictly higher rating.
  • k is never larger than the number of brands.
  • Each line is "rank. Brand (rating)", starting at rank 1.
  • Print the lines, one per line, with println(...).

Start with the two declarations val used = BooleanArray(ratings.size) and val lines = mutableListOf<String>(). A flag tells whether that position is already taken.

Each round is v3's search: nothing found yet, scan every position, skip taken ones, keep the first candidate and replace it only on a strictly higher rating. Then mark the winner as taken and add its line.

        val brands = arrayOf("TechPro", "MegaCorp", "Quantum", "NeoByte", "Zenith")
        val ratings = intArrayOf(4, 5, 3, 5, 4)
        val k = 3

        val used = BooleanArray(ratings.size)
        val lines = mutableListOf<String>()
        for (rank in 1..k) {
            var bestIndex = -1
            for (i in ratings.indices) {
                if (!used[i]) {
                    if (bestIndex == -1 || ratings[i] > ratings[bestIndex]) {
                        bestIndex = i
                    }
                }
            }
            used[bestIndex] = true
            lines.add("$rank. ${brands[bestIndex]} (${ratings[bestIndex]})")
        }
        println(lines.joinToString("\n"))

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    Top K Brands V4 in Kotlin

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