feat: add solutions to lc problems: No.2803,2804 (doocs#1385)

* No.2803.Factorial Generator
* No.2804.Array Prototype ForEach

Author: yanglbme

solution/2800-2899/2803.Factorial Generator/README.md

@@ -0,0 +1,87 @@
+# [2803. Factorial Generator](https://leetcode.cn/problems/factorial-generator)
+
+[English Version](/solution/2800-2899/2803.Factorial%20Generator/README_EN.md)
+
+## 题目描述
+
+<!-- 这里写题目描述 -->
+
+<p>Write a generator function that takes an integer <code>n</code> as an argument and returns a generator object which yields the <strong>factorial sequence</strong>.</p>
+
+<p>The&nbsp;<strong>factorial sequence</strong>&nbsp;is defined by the relation <code>n!&nbsp;= n *&nbsp;<span style="font-size: 13px;">(</span>n-1)&nbsp;* (n-2)&nbsp;*&nbsp;...&nbsp;* 2 * 1​​​.</code></p>
+
+<p>The factorial of 0 is defined as 1.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 5
+<strong>Output:</strong> [1,2,6,24,120]
+<strong>Explanation:</strong> 
+const gen = factorial(5)
+gen.next().value // 1
+gen.next().value // 2
+gen.next().value // 6
+gen.next().value // 24
+gen.next().value // 120
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 2
+<strong>Output:</strong> [1,2]
+<strong>Explanation:</strong> 
+const gen = factorial(2) 
+gen.next().value // 1 
+gen.next().value // 2 
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 0
+<strong>Output:</strong> [1]
+<strong>Explanation:</strong> 
+const gen = factorial(0) 
+gen.next().value // 1 
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>0 &lt;= n &lt;= 18</code></li>
+</ul>
+
+## 解法
+
+<!-- 这里可写通用的实现逻辑 -->
+
+<!-- tabs:start -->
+
+### **TypeScript**
+
+<!-- 这里可写当前语言的特殊实现逻辑 -->
+
+```ts
+function* factorial(n: number): Generator<number> {
+    if (n === 0) {
+        yield 1;
+    }
+    let ans = 1;
+    for (let i = 1; i <= n; ++i) {
+        ans *= i;
+        yield ans;
+    }
+}
+
+/**
+ * const gen = factorial(2);
+ * gen.next().value; // 1
+ * gen.next().value; // 2
+ */
+```
+
+<!-- tabs:end -->

solution/2800-2899/2803.Factorial Generator/README_EN.md

@@ -0,0 +1,81 @@
+# [2803. Factorial Generator](https://leetcode.com/problems/factorial-generator)
+
+[中文文档](/solution/2800-2899/2803.Factorial%20Generator/README.md)
+
+## Description
+
+<p>Write a generator function that takes an integer <code>n</code> as an argument and returns a generator object which yields the <strong>factorial sequence</strong>.</p>
+
+<p>The&nbsp;<strong>factorial sequence</strong>&nbsp;is defined by the relation <code>n!&nbsp;= n *&nbsp;<span style="font-size: 13px;">(</span>n-1)&nbsp;* (n-2)&nbsp;*&nbsp;...&nbsp;* 2 * 1​​​.</code></p>
+
+<p>The factorial of 0 is defined as 1.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 5
+<strong>Output:</strong> [1,2,6,24,120]
+<strong>Explanation:</strong> 
+const gen = factorial(5)
+gen.next().value // 1
+gen.next().value // 2
+gen.next().value // 6
+gen.next().value // 24
+gen.next().value // 120
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 2
+<strong>Output:</strong> [1,2]
+<strong>Explanation:</strong> 
+const gen = factorial(2) 
+gen.next().value // 1 
+gen.next().value // 2 
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> n = 0
+<strong>Output:</strong> [1]
+<strong>Explanation:</strong> 
+const gen = factorial(0) 
+gen.next().value // 1 
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>0 &lt;= n &lt;= 18</code></li>
+</ul>
+
+## Solutions
+
+<!-- tabs:start -->
+
+### **TypeScript**
+
+```ts
+function* factorial(n: number): Generator<number> {
+    if (n === 0) {
+        yield 1;
+    }
+    let ans = 1;
+    for (let i = 1; i <= n; ++i) {
+        ans *= i;
+        yield ans;
+    }
+}
+
+/**
+ * const gen = factorial(2);
+ * gen.next().value; // 1
+ * gen.next().value; // 2
+ */
+```
+
+<!-- tabs:end -->

solution/2800-2899/2803.Factorial Generator/Solution.ts

@@ -0,0 +1,16 @@
+function* factorial(n: number): Generator<number> {
+    if (n === 0) {
+        yield 1;
+    }
+    let ans = 1;
+    for (let i = 1; i <= n; ++i) {
+        ans *= i;
+        yield ans;
+    }
+}
+
+/**
+ * const gen = factorial(2);
+ * gen.next().value; // 1
+ * gen.next().value; // 2
+ */

solution/2800-2899/2804.Array Prototype ForEach/README.md

@@ -0,0 +1,102 @@
+# [2804. Array Prototype ForEach](https://leetcode.cn/problems/array-prototype-foreach)
+
+[English Version](/solution/2800-2899/2804.Array%20Prototype%20ForEach/README_EN.md)
+
+## 题目描述
+
+<!-- 这里写题目描述 -->
+
+<p>Write your version of method&nbsp;<code>forEach</code>&nbsp;that enhances all arrays such that you can call the&nbsp;<code>array.forEach(callback, context)</code>&nbsp;method on any array and it will execute <code>callback</code> on each element of the array.&nbsp;Method&nbsp;<code>forEach</code> should not return anything.</p>
+
+<p><code>callback</code> accepts the following arguments:</p>
+
+<ul>
+	<li><code>value</code> -&nbsp;represents the current element being processed in the array. It is the value of the element in the current iteration.</li>
+	<li><code>index</code> -&nbsp;represents the index of the current element being processed in the array.</li>
+	<li><code>array</code> -&nbsp;represents the array itself, allowing access to the entire array within the callback function.</li>
+</ul>
+
+<p>The <code>context</code> is the object that should be passed as the function context parameter to the <code>callback</code> function, ensuring that the <code>this</code>&nbsp;keyword within the <code>callback</code> function refers to this <code>context</code> object.</p>
+
+<p>Try to implement it without using the built-in array methods.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [1,2,3], 
+callback = (val, i, arr) =&gt; arr[i] = val * 2, 
+context = {&quot;context&quot;:true}
+<strong>Output:</strong> [2,4,6]
+<strong>Explanation:</strong> 
+arr.forEach(callback, context)&nbsp; 
+console.log(arr) // [2,4,6]
+
+The callback is executed on each element of the array.
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [true, true, false, false], 
+callback = (val, i, arr) =&gt; arr[i] = this, 
+context = {&quot;context&quot;: false}
+<strong>Output:</strong> [{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false}]
+<strong>Explanation:</strong> 
+arr.forEach(callback, context)&nbsp;
+console.log(arr) // [{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false}]
+
+The callback is executed on each element of the array with the right context.
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [true, true, false, false], 
+callback = (val, i, arr) =&gt; arr[i] = !val, 
+context = {&quot;context&quot;: 5}
+<strong>Output:</strong> [false,false,true,true]
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>arr</code> is a valid JSON array</li>
+	<li><code>context</code> is a valid JSON object</li>
+	<li><code>fn</code> is a function</li>
+	<li><code>0 &lt;= arr.length &lt;= 10<sup>5</sup></code></li>
+</ul>
+
+## 解法
+
+<!-- 这里可写通用的实现逻辑 -->
+
+<!-- tabs:start -->
+
+### **TypeScript**
+
+<!-- 这里可写当前语言的特殊实现逻辑 -->
+
+```ts
+Array.prototype.forEach = function (callback: Function, context: any): void {
+    for (let i = 0; i < this.length; ++i) {
+        callback.call(context, this[i], i, this);
+    }
+};
+
+/**
+ *  const arr = [1,2,3];
+ *  const callback = (val, i, arr) => arr[i] = val * 2;
+ *  const context = {"context":true};
+ *
+ *  arr.forEach(callback, context)
+ *
+ *  console.log(arr) // [2,4,6]
+ */
+```
+
+<!-- tabs:end -->

solution/2800-2899/2804.Array Prototype ForEach/README_EN.md

@@ -0,0 +1,96 @@
+# [2804. Array Prototype ForEach](https://leetcode.com/problems/array-prototype-foreach)
+
+[中文文档](/solution/2800-2899/2804.Array%20Prototype%20ForEach/README.md)
+
+## Description
+
+<p>Write your version of method&nbsp;<code>forEach</code>&nbsp;that enhances all arrays such that you can call the&nbsp;<code>array.forEach(callback, context)</code>&nbsp;method on any array and it will execute <code>callback</code> on each element of the array.&nbsp;Method&nbsp;<code>forEach</code> should not return anything.</p>
+
+<p><code>callback</code> accepts the following arguments:</p>
+
+<ul>
+	<li><code>value</code> -&nbsp;represents the current element being processed in the array. It is the value of the element in the current iteration.</li>
+	<li><code>index</code> -&nbsp;represents the index of the current element being processed in the array.</li>
+	<li><code>array</code> -&nbsp;represents the array itself, allowing access to the entire array within the callback function.</li>
+</ul>
+
+<p>The <code>context</code> is the object that should be passed as the function context parameter to the <code>callback</code> function, ensuring that the <code>this</code>&nbsp;keyword within the <code>callback</code> function refers to this <code>context</code> object.</p>
+
+<p>Try to implement it without using the built-in array methods.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [1,2,3], 
+callback = (val, i, arr) =&gt; arr[i] = val * 2, 
+context = {&quot;context&quot;:true}
+<strong>Output:</strong> [2,4,6]
+<strong>Explanation:</strong> 
+arr.forEach(callback, context)&nbsp; 
+console.log(arr) // [2,4,6]
+
+The callback is executed on each element of the array.
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [true, true, false, false], 
+callback = (val, i, arr) =&gt; arr[i] = this, 
+context = {&quot;context&quot;: false}
+<strong>Output:</strong> [{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false}]
+<strong>Explanation:</strong> 
+arr.forEach(callback, context)&nbsp;
+console.log(arr) // [{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false},{&quot;context&quot;:false}]
+
+The callback is executed on each element of the array with the right context.
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> 
+arr = [true, true, false, false], 
+callback = (val, i, arr) =&gt; arr[i] = !val, 
+context = {&quot;context&quot;: 5}
+<strong>Output:</strong> [false,false,true,true]
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>arr</code> is a valid JSON array</li>
+	<li><code>context</code> is a valid JSON object</li>
+	<li><code>fn</code> is a function</li>
+	<li><code>0 &lt;= arr.length &lt;= 10<sup>5</sup></code></li>
+</ul>
+
+## Solutions
+
+<!-- tabs:start -->
+
+### **TypeScript**
+
+```ts
+Array.prototype.forEach = function (callback: Function, context: any): void {
+    for (let i = 0; i < this.length; ++i) {
+        callback.call(context, this[i], i, this);
+    }
+};
+
+/**
+ *  const arr = [1,2,3];
+ *  const callback = (val, i, arr) => arr[i] = val * 2;
+ *  const context = {"context":true};
+ *
+ *  arr.forEach(callback, context)
+ *
+ *  console.log(arr) // [2,4,6]
+ */
+```
+
+<!-- tabs:end -->