solved 9

JimAlexBerger · JimAlexBerger · commit 1090e6c92fae · 2023-10-02T19:40:15.000+02:00
diff --git a/src/solution/mod.rs b/src/solution/mod.rs
@@ -1 +1,2 @@
 mod s0001_two_sum;mod s0167_two_sum_ii_input_array_is_sorted;
+mod s0009_palindrome_number;
diff --git a/src/solution/s0009_palindrome_number.rs b/src/solution/s0009_palindrome_number.rs
@@ -0,0 +1,91 @@
+/**
+ * [9] Palindrome Number
+ *
+ * Given an integer x, return true if x is a <span data-keyword="palindrome-integer">palindrome</span>, and false otherwise.
+ *  
+ * <strong class="example">Example 1:
+ * 
+ * Input: x = 121
+ * Output: true
+ * Explanation: 121 reads as 121 from left to right and from right to left.
+ * 
+ * <strong class="example">Example 2:
+ * 
+ * Input: x = -121
+ * Output: false
+ * Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
+ * 
+ * <strong class="example">Example 3:
+ * 
+ * Input: x = 10
+ * Output: false
+ * Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
+ * 
+ *  
+ * Constraints:
+ * 
+ * 	-2^31 <= x <= 2^31 - 1
+ * 
+ *  
+ * Follow up: Could you solve it without converting the integer to a string?
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/palindrome-number/
+// discuss: https://leetcode.com/problems/palindrome-number/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn is_palindrome(x: i32) -> bool {
+        fn make_palindrome(pre: i32, x: i32) -> i32 {            
+            if (x < 10) {
+                return pre * 10 + x;
+            } else {
+                let d = x % 10;
+                return make_palindrome(pre * 10 + d, x / 10);
+            }        
+        }
+
+        if x < 0 {
+            return false; 
+        } else {
+            return x == make_palindrome(0, x);
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let input = 123;
+        let res = Solution::is_palindrome(input);
+        assert_eq!(false, res);
+    }
+
+    #[test]
+    fn test_2() {
+        let input = 1;
+        let res = Solution::is_palindrome(input);
+        assert_eq!(true, res);
+    }
+
+    #[test]
+    fn test_3() {
+        let input = 313;
+        let res = Solution::is_palindrome(input);
+        assert_eq!(true, res);
+    }
+
+    #[test]
+    fn test_4() {
+        let input = -123;
+        let res = Solution::is_palindrome(input);
+        assert_eq!(false, res);
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -1 +1,2 @@`
`1`	`1`	`mod s0001_two_sum;mod s0167_two_sum_ii_input_array_is_sorted;`
	`2`	`+mod s0009_palindrome_number;`