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Author: dingjikerbo

leetcode/solution/src/PalindromeNumber.java

@@ -1,5 +1,6 @@
 public class PalindromeNumber {
 
+    // 耗时101ms
     public boolean isPalindrome(int x) {
         if (x < 0) {
             return false;
@@ -16,4 +17,19 @@ public boolean isPalindrome(int x) {
 
         return true;
     }
+
+    /**
+     * 直接给数倒过来看是否相等
+     * 耗时103ms
+     */
+    public boolean isPalindrome2(int x) {
+        if (x < 0) {
+            return false;
+        }
+        int n = 0, m = x;
+        for ( ; x > 0; x /= 10) {
+            n = n * 10 + x % 10;
+        }
+        return n == m;
+    }
 }

leetcode/src/Main.java

@@ -2,18 +2,15 @@
 
 public class Main {
 
-    public int[] productExceptSelf(int[] nums) {
-        int[] res = new int[nums.length];
-        int left = 1, right = 1;
-        for (int i = 0; i < nums.length; i++) {
-            res[i] = left;
-            left *= nums[i];
+    public boolean isPalindrome(int x) {
+        if (x < 0) {
+            return false;
         }
-        for (int i = nums.length - 1; i >= 0; i--) {
-            res[i] *= right;
-            right *= nums[i];
+        int n = 0, m = x;
+        for ( ; x > 0; x /= 10) {
+            n = n * 10 + x % 10;
         }
-        return res;
+        return n == m;
     }
 
     public static void main(String[] args) {