enhance swapChar

main.cpp

@@ -100,9 +100,12 @@ bool isValidPlayer(char c) {
 }
 
 void swapChar(char &a, char &b) {
-    char temp = a;
-    a = b;
-    b = temp;
+    if (a == b) {
+        return;
+    }
+    a ^= b;
+    b ^= a;
+    a ^= b;
 }
 
 // Recursively reverse a string
@@ -112,6 +115,7 @@ void reverseString(string &str, int start, int end) {
     }
 
     swapChar(str[start], str[end]);
+
     reverseString(str, start + 1, end - 1);
 }