Create 1553-minimum-number-of-days-to-eat-n-oranges.kt

Author: a93a

kotlin/1553-minimum-number-of-days-to-eat-n-oranges.kt

@@ -0,0 +1,72 @@
+// dfs
+class Solution {
+    fun minDays(n: Int): Int {
+        val dp = HashMap<Int, Int>().apply {
+            this[0] = 0
+            this[1] = 1
+        }
+
+        fun dfs(n: Int): Int {
+            if (n in dp) return dp[n]!!
+
+            val divByTwo = 1 + (n % 2) + dfs(n / 2)
+            val divByThree = 1 + (n % 3) + dfs(n / 3)
+
+            dp[n] = minOf(
+                divByTwo,
+                divByThree
+            )
+
+            return dp[n]!!
+        }
+
+        return dfs(n)
+    }
+}
+
+// Bonus: same as above but with more compact code
+class Solution {
+    fun minDays(n: Int): Int {
+        val dp = HashMap<Int, Int>()
+
+        fun dfs(n: Int): Int {
+            if (n <= 1) return n
+            
+            if (n !in dp) {
+                dp[n] = minOf(
+                    1 + (n % 2) + dfs(n / 2),
+                    1 + (n % 3) + dfs(n / 3)
+                )
+            }
+
+            return dp[n]!!
+        }
+
+        return dfs(n)
+    }
+}
+
+// bfs
+class Solution {
+    fun minDays(n: Int): Int {
+        val q = LinkedList<Int>().apply { add(n) }
+        val visited = HashSet<Int>()
+        var days = 1
+
+        while (q.isNotEmpty()) {
+            repeat (q.size) {
+                val n = q.removeFirst()
+                if (n == 1 || n == 0) return days
+                if (n !in visited) {
+                    visited.add(n)
+                    q.addLast(n - 1)
+                    if (n % 2 == 0) q.addLast(n / 2)
+                    if (n % 3 == 0) q.addLast(n / 3)
+                }   
+            }
+            days++
+        }
+
+        return days
+    }
+}