feat: add typescript solution to lc problem: No.1619.Mean of Array After Removing Some Elements (doocs#578)

Author: zhaocchen

solution/1600-1699/1619.Mean of Array After Removing Some Elements/README.md

@@ -81,6 +81,20 @@
 
 ```
 
+### **TypeScript**
+
+```ts
+function trimMean(arr: number[]): number {
+    arr.sort((a, b) => a - b);
+    let n = arr.length, rmLen = n * 0.05;
+    let sum = 0;
+    for (let i = rmLen; i < n - rmLen; i++) {
+        sum += arr[i];
+    }
+    return sum / (n * 0.9);
+};
+```
+
 ### **...**
 
 ```

solution/1600-1699/1619.Mean of Array After Removing Some Elements/README_EN.md

@@ -71,6 +71,20 @@
 
 ```
 
+### **TypeScript**
+
+```ts
+function trimMean(arr: number[]): number {
+    arr.sort((a, b) => a - b);
+    let n = arr.length, rmLen = n * 0.05;
+    let sum = 0;
+    for (let i = rmLen; i < n - rmLen; i++) {
+        sum += arr[i];
+    }
+    return sum / (n * 0.9);
+};
+```
+
 ### **...**
 
 ```

solution/1600-1699/1619.Mean of Array After Removing Some Elements/Solution.ts

@@ -0,0 +1,9 @@
+function trimMean(arr: number[]): number {
+    arr.sort((a, b) => a - b);
+    let n = arr.length, rmLen = n * 0.05;
+    let sum = 0;
+    for (let i = rmLen; i < n - rmLen; i++) {
+        sum += arr[i];
+    }
+    return sum / (n * 0.9);
+};