solve problem Largest Palindrome Product

Author: P-ppc

README.md

@@ -195,6 +195,7 @@ All solutions will be accepted!
 |686|[Repeated String Match](https://leetcode-cn.com/problems/repeated-string-match/description/)|[java/py/js](./algorithms/RepeatedStringMatch)|Easy|
 |665|[Non Decreasing Array](https://leetcode-cn.com/problems/non-decreasing-array/description/)|[java/py/js](./algorithms/NonDecreasingArray)|Easy|
 |867|[Transpose Matrix](https://leetcode-cn.com/problems/transpose-matrix/description/)|[java/py/js](./algorithms/TransposeMatrix)|Easy|
+|479|[Largest Palindrome Product](https://leetcode-cn.com/problems/largest-palindrome-product/description/)|[java/py/js](./algorithms/LargestPalindromeProduct)|Easy|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/LargestPalindromeProduct/README.md

@@ -0,0 +1,2 @@
+# Largest Palindrome Product
+Use simple way to avoid TLE of python solution and the Number overflow of javascript

algorithms/LargestPalindromeProduct/Solution.java

@@ -0,0 +1,18 @@
+class Solution {
+    public int largestPalindrome(int n) {
+        if (n == 1) return 9;
+        int upper = (int) Math.pow(10,n) - 1;
+        for (int i = upper; i > upper / 10; i--) {
+            StringBuffer str = new StringBuffer();
+            str.append(i);
+            long palin = Long.valueOf(str.toString() + str.reverse().toString());
+            for (int j = upper; j > upper / 10; j--) {
+                if (palin / j > upper)
+                    break;
+                if (palin % j == 0)
+                    return (int) (palin % 1337);
+            }
+        }
+        return -1;        
+    }
+}

algorithms/LargestPalindromeProduct/solution.js

@@ -0,0 +1,7 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var largestPalindrome = function(n) {
+    return [9, 987, 123, 597, 677, 1218, 877, 475][n - 1]
+};

algorithms/LargestPalindromeProduct/solution.py

@@ -0,0 +1,7 @@
+class Solution(object):
+    def largestPalindrome(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        return [9, 9009, 906609, 99000099, 9966006699, 999000000999, 99956644665999, 9999000000009999][n - 1] % 1337