feat: add maximum product three numbers solution

sandrig · Jul 28, 2023 · c0069cc · c0069cc
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diff --git a/README.md b/README.md
@@ -2,16 +2,17 @@
 
 ## Easy
 
-| #   | Problem                                                                               | Solution                                                                                                     | Time       | Space  | Tag                          |
-| --- | ------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ | ---------- | ------ | ---------------------------- |
-| 1   | [Two Sum](https://leetcode.com/problems/two-sum/)                                     | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/twoSum/README.md)                | _O(n)_     | _O(n)_ | Array, Hash Table            |
-| 2   | [Move Zeroes](https://leetcode.com/problems/move-zeroes/)                             | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/moveZeroes/README.md)            | _O(n)_     | _O(1)_ | Array, Two Pointers          |
-| 3   | [Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)                   | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/validPalindrome/README.md)       | _O(n)_     | _O(n)_ | String, Two Pointers         |
-| 4   | [Summary Ranges](https://leetcode.com/problems/summary-ranges/)                       | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/summaryRanges/README.md)         | _O(n)_     | _O(n)_ | Array                        |
-| 5   | [Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)       | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/mergeTwoSortedLists/README.md)   | _O(n + m)_ | _O(1)_ | Linked List, Recursion       |
-| 6   | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array/) | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/squaresOfaSortedArray/README.md) | _O(n)_     | _O(n)_ | Array, Two Pointers, Sorting |
-| 7   | [Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)             | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/reverseLinkedList/README.md)     | _O(n)_     | _O(1)_ | Linked List, Recursion       |
-| 8   | [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)                 | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/validParentheses/README.md)      | _O(n)_     | _O(n)_ | String, Stack                |
+| #   | Problem                                                                                             | Solution                                                                                                            | Time       | Space  | Tag                          |
+| --- | --------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ---------- | ------ | ---------------------------- |
+| 1   | [Two Sum](https://leetcode.com/problems/two-sum/)                                                   | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/twoSum/README.md)                       | _O(n)_     | _O(n)_ | Array, Hash Table            |
+| 2   | [Move Zeroes](https://leetcode.com/problems/move-zeroes/)                                           | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/moveZeroes/README.md)                   | _O(n)_     | _O(1)_ | Array, Two Pointers          |
+| 3   | [Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)                                 | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/validPalindrome/README.md)              | _O(n)_     | _O(n)_ | String, Two Pointers         |
+| 4   | [Summary Ranges](https://leetcode.com/problems/summary-ranges/)                                     | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/summaryRanges/README.md)                | _O(n)_     | _O(n)_ | Array                        |
+| 5   | [Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)                     | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/mergeTwoSortedLists/README.md)          | _O(n + m)_ | _O(1)_ | Linked List, Recursion       |
+| 6   | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array/)               | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/squaresOfaSortedArray/README.md)        | _O(n)_     | _O(n)_ | Array, Two Pointers, Sorting |
+| 7   | [Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)                           | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/reverseLinkedList/README.md)            | _O(n)_     | _O(1)_ | Linked List, Recursion       |
+| 8   | [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)                               | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/validParentheses/README.md)             | _O(n)_     | _O(n)_ | String, Stack                |
+| 9   | [Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers/) | [TypeScript](https://github.com/sandrig/leetcode/blob/master/typescript/src/maximumProductofThreeNumbers/README.md) | _O(n)_     | _O(1)_ | Array, Math, Sorting         |
 
 ## Medium
 

diff --git a/typescript/src/maximumProductofThreeNumbers/README.md b/typescript/src/maximumProductofThreeNumbers/README.md
@@ -0,0 +1,51 @@
+# [Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers/)
+
+## Description
+
+Given an integer array **nums**, find three numbers whose product is maximum and return the maximum product.
+
+**Example 1:**
+
+```
+Input: nums = [1,2,3]
+Output: 6
+```
+
+**Example 2:**
+
+```
+Input: nums = [1,2,3,4]
+Output: 24
+```
+
+**Example 3:**
+
+```
+Input: nums = [-1,-2,-3]
+Output: -6
+```
+
+## Solution
+
+```typescript
+function maximumProduct(nums: number[]): number {
+  // First sort the array in ascending order
+  nums.sort((a, b) => a - b);
+
+  const n = nums.length;
+
+  // Product of three maximum elements
+  const product1 = nums[n - 1] * nums[n - 2] * nums[n - 3];
+
+  // The product of two minimum elements and a maximum element
+  const product2 = nums[0] * nums[1] * nums[n - 1];
+
+  // Return the maximum of the two products found
+  return Math.max(product1, product2);
+}
+```
+
+## Complexity Analysis
+
+- Time complexity: _O(n)_
+- Space complexity: _O(1)_
diff --git a/typescript/src/maximumProductofThreeNumbers/maximumProduct.test.ts b/typescript/src/maximumProductofThreeNumbers/maximumProduct.test.ts
@@ -0,0 +1,23 @@
+import { maximumProduct } from "./maximumProduct";
+
+describe("Maximum Product of Three Numbers", () => {
+  it("should return the maximum product of three numbers in the array", () => {
+    const testCases = [
+      { input: [1, 2, 3], output: 6 },
+      { input: [1, 2, 3, 4], output: 24 },
+      { input: [-1, -2, -3], output: -6 },
+      { input: [-1, -2, -3, 0], output: 0 },
+      { input: [10, -10, 1, 2, 3], output: 300 },
+    ];
+
+    for (const testCase of testCases) {
+      const result = maximumProduct(testCase.input);
+      expect(result).toBe(testCase.output);
+    }
+  });
+
+  it("should return 0 if the array contains less than 3 elements", () => {
+    const result = maximumProduct([1, 2]);
+    expect(result).toBe(0);
+  });
+});
diff --git a/typescript/src/maximumProductofThreeNumbers/maximumProduct.ts b/typescript/src/maximumProductofThreeNumbers/maximumProduct.ts
@@ -0,0 +1,15 @@
+export function maximumProduct(nums: number[]): number {
+  // First sort the array in ascending order
+  nums.sort((a, b) => a - b);
+
+  const n = nums.length;
+
+  // Product of three maximum elements
+  const product1 = nums[n - 1] * nums[n - 2] * nums[n - 3];
+
+  // The product of two minimum elements and a maximum element
+  const product2 = nums[0] * nums[1] * nums[n - 1];
+
+  // Return the maximum of the two products found
+  return Math.max(product1, product2);
+}