Update library/signed/src/Comparison.qs

Co-authored-by: César Zaragoza Cortés <[email protected]>
microsoft · Aug 22, 2024 · e3e04ee · e3e04ee
1 parent 9081137
commit e3e04ee
Showing 1 changed file with 9 additions and 8 deletions.
diff --git a/library/signed/src/Comparison.qs b/library/signed/src/Comparison.qs
@@ -16,14 +16,15 @@ import Utils.ApplyCCNOTChain;
 /// Will be flipped if $xs > ys$
 operation CompareGTSI(xs : Qubit[], ys : Qubit[], result : Qubit) : Unit is Adj + Ctl {
     use tmp = Qubit();
-    CNOT(Tail(xs), tmp);
-    CNOT(Tail(ys), tmp);
-    X(tmp);
-    Controlled CompareGTI([tmp], (xs, ys, result));
-    X(tmp);
-    CCNOT(tmp, Tail(ys), result);
-    CNOT(Tail(xs), tmp);
-    CNOT(Tail(ys), tmp);
+    within {
+        CNOT(Tail(xs), tmp);
+        CNOT(Tail(ys), tmp);
+    } apply {
+        X(tmp);
+        Controlled CompareGTI([tmp], (xs, ys, result));
+        X(tmp);
+        CCNOT(tmp, Tail(ys), result);    
+    }
 }