feat: add typescript solution to lc problem: No.1572.Matrix Diagonal Sum

Author: zhaocchen

solution/1500-1599/1572.Matrix Diagonal Sum/README.md

@@ -90,6 +90,23 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function diagonalSum(mat: number[][]): number {
+    let n = mat.length;
+    let ans = 0;
+    for (let i = 0; i < n; i++) {
+        ans += mat[i][i];
+        let j = n - 1 - i;
+        if (i != j) {
+            ans += mat[i][j];
+        }
+    }
+    return ans;
+};
+```
+
 ### **C++**
 
 ```cpp

solution/1500-1599/1572.Matrix Diagonal Sum/README_EN.md

@@ -78,6 +78,23 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function diagonalSum(mat: number[][]): number {
+    let n = mat.length;
+    let ans = 0;
+    for (let i = 0; i < n; i++) {
+        ans += mat[i][i];
+        let j = n - 1 - i;
+        if (i != j) {
+            ans += mat[i][j];
+        }
+    }
+    return ans;
+};
+```
+
 ### **C++**
 
 ```cpp

solution/1500-1599/1572.Matrix Diagonal Sum/Solution.ts

@@ -0,0 +1,12 @@
+function diagonalSum(mat: number[][]): number {
+    let n = mat.length;
+    let ans = 0;
+    for (let i = 0; i < n; i++) {
+        ans += mat[i][i];
+        let j = n - 1 - i;
+        if (i != j) {
+            ans += mat[i][j];
+        }
+    }
+    return ans;
+};