feat: add solutions to lc problems: No.2723,2724

* No.2723.Add Two Promises
* No.2724.Sort By

Author: yanglbme

solution/2700-2799/2723.Add Two Promises/README.md

@@ -47,7 +47,17 @@ promise2 = new Promise(resolve => setTimeout(() => resolve(-12), 30))
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```ts
-
+async function addTwoPromises(
+    promise1: Promise<number>,
+    promise2: Promise<number>,
+): Promise<number> {
+    return (await promise1) + (await promise2);
+}
+
+/**
+ * addTwoPromises(Promise.resolve(2), Promise.resolve(2))
+ *   .then(console.log); // 4
+ */
 ```
 
 <!-- tabs:end -->

solution/2700-2799/2723.Add Two Promises/README_EN.md

@@ -41,7 +41,17 @@ promise2 = new Promise(resolve => setTimeout(() => resolve(-12), 30))
 ### **TypeScript**
 
 ```ts
-
+async function addTwoPromises(
+    promise1: Promise<number>,
+    promise2: Promise<number>,
+): Promise<number> {
+    return (await promise1) + (await promise2);
+}
+
+/**
+ * addTwoPromises(Promise.resolve(2), Promise.resolve(2))
+ *   .then(console.log); // 4
+ */
 ```
 
 <!-- tabs:end -->

solution/2700-2799/2723.Add Two Promises/Solution.ts

@@ -0,0 +1,11 @@
+async function addTwoPromises(
+    promise1: Promise<number>,
+    promise2: Promise<number>,
+): Promise<number> {
+    return (await promise1) + (await promise2);
+}
+
+/**
+ * addTwoPromises(Promise.resolve(2), Promise.resolve(2))
+ *   .then(console.log); // 4
+ */

solution/2700-2799/2724.Sort By/README.md

@@ -55,7 +55,9 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```ts
-
+function sortBy(arr: any[], fn: Function): any[] {
+    return arr.sort((a, b) => fn(a) - fn(b));
+}
 ```
 
 <!-- tabs:end -->

solution/2700-2799/2724.Sort By/README_EN.md

@@ -49,7 +49,9 @@
 ### **TypeScript**
 
 ```ts
-
+function sortBy(arr: any[], fn: Function): any[] {
+    return arr.sort((a, b) => fn(a) - fn(b));
+}
 ```
 
 <!-- tabs:end -->

solution/2700-2799/2724.Sort By/Solution.ts

@@ -0,0 +1,3 @@
+function sortBy(arr: any[], fn: Function): any[] {
+    return arr.sort((a, b) => fn(a) - fn(b));
+}