Add solution for #11 Container With Most Water.

Author: ecgan

problems/container-with-most-water/README.md

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+# Container With Most Water
+
+LeetCode #: [11](https://leetcode.com/problems/container-with-most-water/)
+
+Difficulty: Medium
+
+Topics: Array, Two Pointers.
+
+## Problem
+
+Given `n` non-negative integers `a1, a2, ..., an` , where each represents a point at coordinate `(i, ai)`. `n` vertical lines are drawn such that the two endpoints of the line `i` is at `(i, ai)` and `(i, 0)`. Find two lines, which, together with the x-axis forms a container, such that the container contains the most water.
+
+Notice that you may not slant the container.
+
+Example 1:
+
+![Example 1](https://s3-lc-upload.s3.amazonaws.com/uploads/2018/07/17/question_11.jpg)
+
+```text
+Input: height = [1,8,6,2,5,4,8,3,7]
+Output: 49
+Explanation: The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.
+```
+
+Example 2:
+
+```text
+Input: height = [1,1]
+Output: 1
+```
+
+Example 3:
+
+```text
+Input: height = [4,3,2,1,4]
+Output: 16
+```
+
+Example 4:
+
+```text
+Input: height = [1,2,1]
+Output: 2
+```
+
+Constraints:
+
+- `n == height.length`
+- `2 <= n <= 3 * 10^4`
+- `0 <= height[i] <= 3 * 10^4`

problems/container-with-most-water/maxArea.js

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+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+const maxArea = (height) => {
+  let left = 0
+  let right = height.length - 1
+  let area = 0
+
+  while (left < right) {
+    const w = right - left
+    const h = Math.min(height[left], height[right])
+    area = Math.max(area, w * h)
+
+    if (height[left] < height[right]) {
+      left++
+    } else {
+      right--
+    }
+  }
+
+  return area
+}
+
+module.exports = maxArea

problems/container-with-most-water/maxArea.test.js

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+const maxArea = require('./maxArea')
+
+test('Example 1', () => {
+  const height = [1, 8, 6, 2, 5, 4, 8, 3, 7]
+
+  const result = maxArea(height)
+
+  expect(result).toStrictEqual(49)
+})
+
+test('Example 2', () => {
+  const height = [1, 1]
+
+  const result = maxArea(height)
+
+  expect(result).toStrictEqual(1)
+})
+
+test('Example 3', () => {
+  const height = [4, 3, 2, 1, 4]
+
+  const result = maxArea(height)
+
+  expect(result).toStrictEqual(16)
+})
+
+test('Example 4', () => {
+  const height = [1, 2, 1]
+
+  const result = maxArea(height)
+
+  expect(result).toStrictEqual(2)
+})