refactor some promise with batch concurrency

Notes/Questions/0590__n-ary-tree-postorder-traversal/readme.md

@@ -13,7 +13,7 @@
 </pre>
 
 <p><strong>Example 2:</strong></p>
-<img alt="" src="sample_4_964.png" style="width: 296px; height: 241px;" />
+<img alt="" src="https://assets.leetcode.com/uploads/2019/11/08/sample_4_964.png" style="width: 296px; height: 241px;" />
 <pre>
 <strong>Input:</strong> root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14]
 <strong>Output:</strong> [2,6,14,11,7,3,12,8,4,13,9,10,5,1]

Notes/Questions/2090__k-radius-subarray-averages/readme.md

@@ -14,7 +14,7 @@
 
 <p>&nbsp;</p>
 <p><strong>Example 1:</strong></p>
-<img alt="" src="eg1.png" style="width: 343px; height: 119px;" />
+<img alt="" src="https://assets.leetcode.com/uploads/2021/11/07/eg1.png" style="width: 343px; height: 119px;" />
 <pre>
 <strong>Input:</strong> nums = [7,4,3,9,1,8,5,2,6], k = 3
 <strong>Output:</strong> [-1,-1,-1,5,4,4,-1,-1,-1]

Notes/Questions/2200__find-all-k-distant-indices-in-an-array/readme.md

@@ -0,0 +1,41 @@
+# Problem Statement
+
+<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> and two integers <code>key</code> and <code>k</code>. A <strong>k-distant index</strong> is an index <code>i</code> of <code>nums</code> for which there exists at least one index <code>j</code> such that <code>|i - j| &lt;= k</code> and <code>nums[j] == key</code>.</p>
+
+<p>Return <em>a list of all k-distant indices sorted in <strong>increasing order</strong></em>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [3,4,9,1,3,9,5], key = 9, k = 1
+<strong>Output:</strong> [1,2,3,4,5,6]
+<strong>Explanation:</strong> Here, <code>nums[2] == key</code> and <code>nums[5] == key.
+- For index 0, |0 - 2| &gt; k and |0 - 5| &gt; k, so there is no j</code> where <code>|0 - j| &lt;= k</code> and <code>nums[j] == key. Thus, 0 is not a k-distant index.
+- For index 1, |1 - 2| &lt;= k and nums[2] == key, so 1 is a k-distant index.
+- For index 2, |2 - 2| &lt;= k and nums[2] == key, so 2 is a k-distant index.
+- For index 3, |3 - 2| &lt;= k and nums[2] == key, so 3 is a k-distant index.
+- For index 4, |4 - 5| &lt;= k and nums[5] == key, so 4 is a k-distant index.
+- For index 5, |5 - 5| &lt;= k and nums[5] == key, so 5 is a k-distant index.
+- For index 6, |6 - 5| &lt;= k and nums[5] == key, so 6 is a k-distant index.
+</code>Thus, we return [1,2,3,4,5,6] which is sorted in increasing order. 
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [2,2,2,2,2], key = 2, k = 2
+<strong>Output:</strong> [0,1,2,3,4]
+<strong>Explanation:</strong> For all indices i in nums, there exists some index j such that |i - j| &lt;= k and nums[j] == key, so every index is a k-distant index. 
+Hence, we return [0,1,2,3,4].
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 1000</code></li>
+	<li><code>1 &lt;= nums[i] &lt;= 1000</code></li>
+	<li><code>key</code> is an integer from the array <code>nums</code>.</li>
+	<li><code>1 &lt;= k &lt;= nums.length</code></li>
+</ul>

Notes/Questions/2201__count-artifacts-that-can-be-extracted/readme.md

@@ -0,0 +1,57 @@
+# Problem Statement
+
+<p>There is an <code>n x n</code> <strong>0-indexed</strong> grid with some artifacts buried in it. You are given the integer <code>n</code> and a <strong>0-indexed </strong>2D integer array <code>artifacts</code> describing the positions of the rectangular artifacts where <code>artifacts[i] = [r1<sub>i</sub>, c1<sub>i</sub>, r2<sub>i</sub>, c2<sub>i</sub>]</code> denotes that the <code>i<sup>th</sup></code> artifact is buried in the subgrid where:</p>
+
+<ul>
+	<li><code>(r1<sub>i</sub>, c1<sub>i</sub>)</code> is the coordinate of the <strong>top-left</strong> cell of the <code>i<sup>th</sup></code> artifact and</li>
+	<li><code>(r2<sub>i</sub>, c2<sub>i</sub>)</code> is the coordinate of the <strong>bottom-right</strong> cell of the <code>i<sup>th</sup></code> artifact.</li>
+</ul>
+
+<p>You will excavate some cells of the grid and remove all the mud from them. If the cell has a part of an artifact buried underneath, it will be uncovered. If all the parts of an artifact are uncovered, you can extract it.</p>
+
+<p>Given a <strong>0-indexed</strong> 2D integer array <code>dig</code> where <code>dig[i] = [r<sub>i</sub>, c<sub>i</sub>]</code> indicates that you will excavate the cell <code>(r<sub>i</sub>, c<sub>i</sub>)</code>, return <em>the number of artifacts that you can extract</em>.</p>
+
+<p>The test cases are generated such that:</p>
+
+<ul>
+	<li>No two artifacts overlap.</li>
+	<li>Each artifact only covers at most <code>4</code> cells.</li>
+	<li>The entries of <code>dig</code> are unique.</li>
+</ul>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+<img alt="" src="untitled-diagram.jpg" style="width: 216px; height: 216px;" />
+<pre>
+<strong>Input:</strong> n = 2, artifacts = [[0,0,0,0],[0,1,1,1]], dig = [[0,0],[0,1]]
+<strong>Output:</strong> 1
+<strong>Explanation:</strong> 
+The different colors represent different artifacts. Excavated cells are labeled with a &#39;D&#39; in the grid.
+There is 1 artifact that can be extracted, namely the red artifact.
+The blue artifact has one part in cell (1,1) which remains uncovered, so we cannot extract it.
+Thus, we return 1.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+<img alt="" src="untitled-diagram-1.jpg" style="width: 216px; height: 216px;" />
+<pre>
+<strong>Input:</strong> n = 2, artifacts = [[0,0,0,0],[0,1,1,1]], dig = [[0,0],[0,1],[1,1]]
+<strong>Output:</strong> 2
+<strong>Explanation:</strong> Both the red and blue artifacts have all parts uncovered (labeled with a &#39;D&#39;) and can be extracted, so we return 2. 
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n &lt;= 1000</code></li>
+	<li><code>1 &lt;= artifacts.length, dig.length &lt;= min(n<sup>2</sup>, 10<sup>5</sup>)</code></li>
+	<li><code>artifacts[i].length == 4</code></li>
+	<li><code>dig[i].length == 2</code></li>
+	<li><code>0 &lt;= r1<sub>i</sub>, c1<sub>i</sub>, r2<sub>i</sub>, c2<sub>i</sub>, r<sub>i</sub>, c<sub>i</sub> &lt;= n - 1</code></li>
+	<li><code>r1<sub>i</sub> &lt;= r2<sub>i</sub></code></li>
+	<li><code>c1<sub>i</sub> &lt;= c2<sub>i</sub></code></li>
+	<li>No two artifacts will overlap.</li>
+	<li>The number of cells covered by an artifact is <strong>at most</strong> <code>4</code>.</li>
+	<li>The entries of <code>dig</code> are unique.</li>
+</ul>

Notes/Questions/2202__maximize-the-topmost-element-after-k-moves/readme.md

@@ -0,0 +1,47 @@
+# Problem Statement
+
+<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> representing the contents of a <b>pile</b>, where <code>nums[0]</code> is the topmost element of the pile.</p>
+
+<p>In one move, you can perform <strong>either</strong> of the following:</p>
+
+<ul>
+	<li>If the pile is not empty, <strong>remove</strong> the topmost element of the pile.</li>
+	<li>If there are one or more removed elements, <strong>add</strong> any one of them back onto the pile. This element becomes the new topmost element.</li>
+</ul>
+
+<p>You are also given an integer <code>k</code>, which denotes the total number of moves to be made.</p>
+
+<p>Return <em>the <strong>maximum value</strong> of the topmost element of the pile possible after <strong>exactly</strong></em> <code>k</code> <em>moves</em>. In case it is not possible to obtain a non-empty pile after <code>k</code> moves, return <code>-1</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [5,2,2,4,0,6], k = 4
+<strong>Output:</strong> 5
+<strong>Explanation:</strong>
+One of the ways we can end with 5 at the top of the pile after 4 moves is as follows:
+- Step 1: Remove the topmost element = 5. The pile becomes [2,2,4,0,6].
+- Step 2: Remove the topmost element = 2. The pile becomes [2,4,0,6].
+- Step 3: Remove the topmost element = 2. The pile becomes [4,0,6].
+- Step 4: Add 5 back onto the pile. The pile becomes [5,4,0,6].
+Note that this is not the only way to end with 5 at the top of the pile. It can be shown that 5 is the largest answer possible after 4 moves.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [2], k = 1
+<strong>Output:</strong> -1
+<strong>Explanation:</strong> 
+In the first move, our only option is to pop the topmost element of the pile.
+Since it is not possible to obtain a non-empty pile after one move, we return -1.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>0 &lt;= nums[i], k &lt;= 10<sup>9</sup></code></li>
+</ul>

Notes/Questions/2203__minimum-weighted-subgraph-with-the-required-paths/readme.md

@@ -0,0 +1,46 @@
+# Problem Statement
+
+<p>You are given an integer <code>n</code> denoting the number of nodes of a <strong>weighted directed</strong> graph. The nodes are numbered from <code>0</code> to <code>n - 1</code>.</p>
+
+<p>You are also given a 2D integer array <code>edges</code> where <code>edges[i] = [from<sub>i</sub>, to<sub>i</sub>, weight<sub>i</sub>]</code> denotes that there exists a <strong>directed</strong> edge from <code>from<sub>i</sub></code> to <code>to<sub>i</sub></code> with weight <code>weight<sub>i</sub></code>.</p>
+
+<p>Lastly, you are given three <strong>distinct</strong> integers <code>src1</code>, <code>src2</code>, and <code>dest</code> denoting three distinct nodes of the graph.</p>
+
+<p>Return <em>the <strong>minimum weight</strong> of a subgraph of the graph such that it is <strong>possible</strong> to reach</em> <code>dest</code> <em>from both</em> <code>src1</code> <em>and</em> <code>src2</code> <em>via a set of edges of this subgraph</em>. In case such a subgraph does not exist, return <code>-1</code>.</p>
+
+<p>A <strong>subgraph</strong> is a graph whose vertices and edges are subsets of the original graph. The <strong>weight</strong> of a subgraph is the sum of weights of its constituent edges.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+<img alt="" src="example1drawio.png" style="width: 263px; height: 250px;" />
+<pre>
+<strong>Input:</strong> n = 6, edges = [[0,2,2],[0,5,6],[1,0,3],[1,4,5],[2,1,1],[2,3,3],[2,3,4],[3,4,2],[4,5,1]], src1 = 0, src2 = 1, dest = 5
+<strong>Output:</strong> 9
+<strong>Explanation:</strong>
+The above figure represents the input graph.
+The blue edges represent one of the subgraphs that yield the optimal answer.
+Note that the subgraph [[1,0,3],[0,5,6]] also yields the optimal answer. It is not possible to get a subgraph with less weight satisfying all the constraints.
+</pre>
+
+<p><strong>Example 2:</strong></p>
+<img alt="" src="example2-1drawio.png" style="width: 350px; height: 51px;" />
+<pre>
+<strong>Input:</strong> n = 3, edges = [[0,1,1],[2,1,1]], src1 = 0, src2 = 1, dest = 2
+<strong>Output:</strong> -1
+<strong>Explanation:</strong>
+The above figure represents the input graph.
+It can be seen that there does not exist any path from node 1 to node 2, hence there are no subgraphs satisfying all the constraints.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>3 &lt;= n &lt;= 10<sup>5</sup></code></li>
+	<li><code>0 &lt;= edges.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>edges[i].length == 3</code></li>
+	<li><code>0 &lt;= from<sub>i</sub>, to<sub>i</sub>, src1, src2, dest &lt;= n - 1</code></li>
+	<li><code>from<sub>i</sub> != to<sub>i</sub></code></li>
+	<li><code>src1</code>, <code>src2</code>, and <code>dest</code> are pairwise distinct.</li>
+	<li><code>1 &lt;= weight[i] &lt;= 10<sup>5</sup></code></li>
+</ul>