kt: add «322. Coin Change»

URL:	https://leetcode.com/problems/coin-change/

kt/coin-change.kt

@@ -0,0 +1,29 @@
+class Solution {
+    fun coinChange(
+        coins: IntArray,
+        amount: Int,
+    ): Int =
+        IntArray(amount + 1) { Int.MAX_VALUE }.let { dp ->
+            // base case
+            dp[0] = 0
+
+            // sort the coins
+            coins.sort()
+
+            // precompute
+            (1..amount).forEach { total ->
+                for (coin in coins) {
+                    when {
+                        total - coin < 0 -> break
+                        dp[total - coin] != Int.MAX_VALUE -> dp[total] = minOf(dp[total], 1 + dp[total - coin])
+                    }
+                }
+            }
+
+            // return the minimum count for the target
+            when {
+                dp[amount] == Int.MAX_VALUE -> -1
+                else -> dp[amount]
+            }
+        }
+}