This article deals with solving problems that frequently appear in job interviews or algorithm tests, presenting a way to develop both the basics of Kotlin and problem-solving skills through the topic of “Gift Giving.” This problem is based on the fundamental concepts of graph theory and provides logic that can be applied in real life.<\/p>\n<\/div>\n
The given array For example, let’s assume the following input is provided:<\/p>\n In this case, each person delivers gifts as follows:<\/p>\n Therefore, 3 actions are needed. Let’s implement an algorithm to solve this problem in Kotlin.<\/p>\n<\/div>\n To solve this problem, we need to clearly understand each person’s gift delivery and identify the delivery cycle structure. By applying simple exception handling, we can skip any person who does not need to deliver a gift.<\/p>\n Below is the Kotlin code implemented according to the approach above:<\/p>\n To test the given function, I created several diverse test cases:<\/p>\ngifts<\/code> contains N people, with the priorities of the gift<\/code> that need to be delivered to each person listed in order. Each person has a specific number of gifts, and these gifts must be delivered to their counterparts. Our goal is to ensure that everyone receives the exact gifts they want exactly once, while calculating the minimum number of gift delivery actions required to achieve this.<\/p>\ngifts = [2, 0, 1, 3]<\/code><\/pre>\n\n
Approach to the Problem<\/h2>\n
Approach<\/h3>\n
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gifts<\/code> as N.<\/li>\nCode Implementation<\/h2>\n
fun minGiftTransfers(gifts: IntArray): Int {\n val visited = BooleanArray(gifts.size)\n var transfers = 0\n\n for (i in gifts.indices) {\n if (!visited[i]) {\n var current = i\n var cycleSize = 0\n\n do {\n visited[current] = true\n current = gifts[current]\n cycleSize++\n } while (current != i)\n\n \/\/ Exclude the axle (1 gift delivered to each other)\n if (cycleSize > 1) {\n transfers += (cycleSize - 1)\n }\n }\n }\n\n return transfers\n}\n\n\/\/ Test case\nfun main() {\n val gifts = intArrayOf(2, 0, 1, 3)\n println(\"The minimum number of actions required for gift delivery is: ${minGiftTransfers(gifts)}\")\n}<\/code><\/pre>\n<\/div>\nTest Cases<\/h2>\n
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gifts = [1, 0]<\/code>
\nexpected output = 1<\/code> (Person 0 delivers to person 1)\n <\/li>\ngifts = [1, 2, 0]<\/code>
\nexpected output = 1<\/code> (3 people are interconnected)\n <\/li>\ngifts = [1, 2, 3, 4, 0]<\/code>
\nexpected output = 4<\/code> (Everyone delivers to a different person)\n <\/li>\ngifts = [0, 1, 2, 3, 4]<\/code>
\nexpected output = 0<\/code> (Delivers to themselves)\n <\/li>\n<\/ul>\n<\/div>\n