swap two element without extra variable

pythonee · pythonee · commit c40e5bd901b4 · 2012-04-12T16:56:00.000+08:00
diff --git a/algorithm/swap.py b/algorithm/swap.py
@@ -0,0 +1,20 @@
+# of course a,b = b,a is the perfect solution
+# this is show how to do swap without third variable
+
+def swap1(a, b):
+    print a,b
+    a = a + b
+    b = a - b
+    a = a - b
+    print a,b
+
+def swap2(a,b):
+    print a,b
+    a ^= b
+    b ^= a
+    a ^= b
+    print a,b
+
+if __name__ == '__main__':
+    swap1(1,2)
+    swap2(1,2)
