<p>You want to build some obstacle courses. You are given a <strong>0-indexed</strong> integer array <code>obstacles</code> of length <code>n</code>, where <code>obstacles[i]</code> describes the height of the <code>i<sup>th</sup></code> obstacle.</p> <p>For every index <code>i</code> between <code>0</code> and <code>n - 1</code> (<strong>inclusive</strong>), find the length of the <strong>longest obstacle course</strong> in <code>obstacles</code> such that:</p> <ul> <li>You choose any number of obstacles between <code>0</code> and <code>i</code> <strong>inclusive</strong>.</li> <li>You must include the <code>i<sup>th</sup></code> obstacle in the course.</li> <li>You must put the chosen obstacles in the <strong>same order</strong> as they appear in <code>obstacles</code>.</li> <li>Every obstacle (except the first) is <strong>taller</strong> than or the <strong>same height</strong> as the obstacle immediately before it.</li> </ul> <p>Return <em>an array</em> <code>ans</code> <em>of length</em> <code>n</code>, <em>where</em> <code>ans[i]</code> <em>is the length of the <strong>longest obstacle course</strong> for index</em> <code>i</code><em> as described above</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> obstacles = [1,2,3,2] <strong>Output:</strong> [1,2,3,3] <strong>Explanation:</strong> The longest valid obstacle course at each position is: - i = 0: [<u>1</u>], [1] has length 1. - i = 1: [<u>1</u>,<u>2</u>], [1,2] has length 2. - i = 2: [<u>1</u>,<u>2</u>,<u>3</u>], [1,2,3] has length 3. - i = 3: [<u>1</u>,<u>2</u>,3,<u>2</u>], [1,2,2] has length 3. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> obstacles = [2,2,1] <strong>Output:</strong> [1,2,1] <strong>Explanation: </strong>The longest valid obstacle course at each position is: - i = 0: [<u>2</u>], [2] has length 1. - i = 1: [<u>2</u>,<u>2</u>], [2,2] has length 2. - i = 2: [2,2,<u>1</u>], [1] has length 1. </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> obstacles = [3,1,5,6,4,2] <strong>Output:</strong> [1,1,2,3,2,2] <strong>Explanation:</strong> The longest valid obstacle course at each position is: - i = 0: [<u>3</u>], [3] has length 1. - i = 1: [3,<u>1</u>], [1] has length 1. - i = 2: [<u>3</u>,1,<u>5</u>], [3,5] has length 2. [1,5] is also valid. - i = 3: [<u>3</u>,1,<u>5</u>,<u>6</u>], [3,5,6] has length 3. [1,5,6] is also valid. - i = 4: [<u>3</u>,1,5,6,<u>4</u>], [3,4] has length 2. [1,4] is also valid. - i = 5: [3,<u>1</u>,5,6,4,<u>2</u>], [1,2] has length 2. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == obstacles.length</code></li> <li><code>1 <= n <= 10<sup>5</sup></code></li> <li><code>1 <= obstacles[i] <= 10<sup>7</sup></code></li> </ul>