Create 9. Palindrome Number.cpp

박현아/leetcode/9. Palindrome Number.cpp

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+//220327
+//leetcode #9 Palindrome Number /Easy
+//https://leetcode.com/problems/palindrome-number/
+
+
+//1
+#include <string>
+
+class Solution {
+public:
+    bool isPalindrome(int x) {
+        string x_s = to_string(x);
+        string x_reversed(x_s);
+
+        std::reverse(x_reversed.begin(), x_reversed.end());
+
+        return (x_s == x_reversed);
+    }
+};
+
+
+//2 faster
+#include <string>
+
+class Solution {
+public:
+    bool isPalindrome(int x) {
+        string x_s = to_string(x);
+
+        if(x_s[0] == '-')
+                return false;
+
+        for(int i = 0; i<(x_s.size()/2); i++){
+            //be careful for the last index of x_s. It is not x_s.size() but x_s.size()-1
+            if(x_s[i] != x_s[x_s.size()-i-1])
+                return false;
+        }
+
+        return true;
+    }
+};