add js solution for longestPalindromeSubseq

problems/0516.最长回文子序列.md

@@ -214,7 +214,29 @@ func longestPalindromeSubseq(s string) int {
 }
 ```
 
+Javascript：
+```javascript
+const longestPalindromeSubseq = (s) => {
+    const strLen = s.length;
+    let dp = Array.from(Array(strLen), () => Array(strLen).fill(0));
+    
+    for(let i = 0; i < strLen; i++) {
+        dp[i][i] = 1;
+    }
 
+    for(let i = strLen - 1; i >= 0; i--) {
+        for(let j = i + 1; j < strLen; j++) {
+            if(s[i] === s[j]) {
+                dp[i][j] = dp[i+1][j-1] + 2;
+            } else {
+                dp[i][j] = Math.max(dp[i+1][j], dp[i][j-1]);
+            }
+        }
+    }
+
+    return dp[0][strLen - 1];
+};
+```
 
 
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