add Maximum Product Subarray solution

Author: HoonDongKang

maximum-product-subarray/HoonDongKang.ts

@@ -0,0 +1,43 @@
+/**
+ * [Problem]: [152] Maximum Product Subarray
+ * (https://leetcode.com/problems/maximum-product-subarray/description/)
+ */
+function maxProduct(nums: number[]): number {
+    // 시간복잡도 O(n^2)
+    // 공간복잡도 O(1)
+    function bruteForce(nums: number[]): number {
+        let maxProduct = nums[0];
+
+        for (let i = 0; i < nums.length; i++) {
+            let product = 1;
+            for (let j = i; j < nums.length; j++) {
+                product *= nums[j];
+                maxProduct = Math.max(maxProduct, product);
+            }
+        }
+
+        return maxProduct;
+    }
+
+    // 시간복잡도 O(n)
+    // 공간복잡도 O(1)
+    function optimizedFunc(nums: number[]): number {
+        let maxResult = nums[0];
+        let minResult = nums[0];
+        let result = nums[0];
+
+        for (let i = 1; i < nums.length; i++) {
+            const num = nums[i];
+
+            if (num < 0) {
+                [maxResult, minResult] = [minResult, maxResult];
+            }
+
+            maxResult = Math.max(num, num * maxResult);
+            minResult = Math.min(num, num * minResult);
+            result = Math.max(result, maxResult);
+        }
+
+        return result;
+    }
+}