add Coin Change solution

Author: HoonDongKang

coin-change/HoonDongKang.ts

@@ -0,0 +1,72 @@
+/**
+ * [Problem]: [322] Coin Change
+ *
+ * (https://leetcode.com/problems/coin-change/description/)
+ */
+function coinChange(coins: number[], amount: number): number {
+    // 시간복잡도: O(c^a)
+    // 공간복잡도: O(a)
+    // Time Exceed
+    function dfsFunc(coins: number[], amount: number): number {
+        if (!amount) return 0;
+        let result = dfs(amount);
+
+        return result <= amount ? result : -1;
+
+        function dfs(remain: number): number {
+            if (remain === 0) return 0;
+            if (remain < 0) return amount + 1;
+
+            let min_count = amount + 1;
+
+            for (let coin of coins) {
+                const result = dfs(remain - coin);
+                min_count = Math.min(min_count, result + 1);
+            }
+
+            return min_count;
+        }
+    }
+    // 시간복잡도: O(ca)
+    // 공간복잡도: O(a)
+    function dpFunc(coins: number[], amount: number): number {
+        const dp = new Array(amount + 1).fill(amount + 1);
+        dp[0] = 0;
+
+        for (let coin of coins) {
+            for (let i = coin; i <= amount; i++) {
+                dp[i] = Math.min(dp[i], dp[i - coin] + 1);
+            }
+        }
+
+        return dp[amount] <= amount ? dp[amount] : -1;
+    }
+
+    // 시간복잡도: O(ca)
+    // 공간복잡도: O(a)
+    function memoizationFunc(coins: number[], amount: number): number {
+        const memo: Record<number, number> = {};
+
+        const result = dfs(amount);
+        return result <= amount ? result : -1;
+
+        function dfs(remain: number): number {
+            if (remain === 0) return 0;
+            if (remain < 0) return amount + 1;
+            if (remain in memo) return memo[remain];
+
+            let min_count = amount + 1;
+
+            for (let coin of coins) {
+                const res = dfs(remain - coin);
+                min_count = Math.min(min_count, res + 1);
+            }
+
+            memo[remain] = min_count;
+
+            return min_count;
+        }
+    }
+
+    return memoizationFunc(coins, amount);
+}