feat: add typescript solution to lc problem: No.0540.Single Element in a Sorted Array (#464)

Author: zhaocchen

solution/0500-0599/0540.Single Element in a Sorted Array/README.md

@@ -29,6 +29,8 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+二分法
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -74,6 +76,24 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function singleNonDuplicate(nums: number[]): number {
+    let left = 0, right = nums.length - 1;
+    while (left < right) {
+        let mid = (left + right) >> 1;
+        if ((mid & 1) == 1) --mid;
+        if (nums[mid] == nums[mid + 1]) {
+            left = mid + 2;
+        } else {
+            right = mid;
+        }
+    }
+    return nums[left];
+};
+```
+
 ### **Go**
 
 ```go

solution/0500-0599/0540.Single Element in a Sorted Array/README_EN.md

@@ -82,6 +82,24 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function singleNonDuplicate(nums: number[]): number {
+    let left = 0, right = nums.length - 1;
+    while (left < right) {
+        let mid = (left + right) >> 1;
+        if ((mid & 1) == 1) --mid;
+        if (nums[mid] == nums[mid + 1]) {
+            left = mid + 2;
+        } else {
+            right = mid;
+        }
+    }
+    return nums[left];
+};
+```
+
 ### **Go**
 
 ```go

solution/0500-0599/0540.Single Element in a Sorted Array/Solution.ts

@@ -0,0 +1,13 @@
+function singleNonDuplicate(nums: number[]): number {
+    let left = 0, right = nums.length - 1;
+    while (left < right) {
+        let mid = (left + right) >> 1;
+        if ((mid & 1) == 1) --mid;
+        if (nums[mid] == nums[mid + 1]) {
+            left = mid + 2;
+        } else {
+            right = mid;
+        }
+    }
+    return nums[left];
+};