添加（0392.判断子序列.md）：增加typescript版本

Author: xiaofei-2020

problems/0392.判断子序列.md

@@ -201,7 +201,32 @@ const isSubsequence = (s, t) => {
 };
 ```
 
+TypeScript：
+
+```typescript
+function isSubsequence(s: string, t: string): boolean {
+    /**
+        dp[i][j]: s的前i-1个，t的前j-1个，最长公共子序列的长度
+     */
+    const sLen: number = s.length,
+        tLen: number = t.length;
+    const dp: number[][] = new Array(sLen + 1).fill(0)
+        .map(_ => new Array(tLen + 1).fill(0));
+    for (let i = 1; i <= sLen; i++) {
+        for (let j = 1; j <= tLen; j++) {
+            if (s[i - 1] === t[j - 1]) {
+                dp[i][j] = dp[i - 1][j - 1] + 1;
+            } else {
+                dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
+            }
+        }
+    }
+    return dp[sLen][tLen] === s.length;
+};
+```
+
 Go：
+
 ```go
 func isSubsequence(s string, t string) bool {
     dp := make([][]int,len(s)+1)