feat: 152. Maximum Product Subarray

Author: gwbaik9717

maximum-product-subarray/gwbaik9717.js

@@ -0,0 +1,39 @@
+// Time complexity: O(n^2)
+// Space complexity: O(n)
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var maxProduct = function (nums) {
+  let answer = nums[0];
+
+  const productGroups = [[]];
+
+  for (let i = 0; i < nums.length; i++) {
+    const productGroup = productGroups.at(-1);
+
+    if (nums[i] === 0) {
+      productGroups.push([]);
+    }
+
+    if (productGroup.length === 0) {
+      productGroup.push(nums[i]);
+      continue;
+    }
+
+    productGroup.push(nums[i] * productGroup.at(-1));
+  }
+
+  for (const group of productGroups) {
+    for (let i = 0; i < group.length; i++) {
+      answer = Math.max(answer, group[i]);
+
+      for (let j = 0; j < i; j++) {
+        answer = Math.max(answer, group[i] / group[j]);
+      }
+    }
+  }
+
+  return answer;
+};