diff --git a/content/strings/Zfunc.h b/content/strings/Zfunc.h
index 2b86f37b3..74b320004 100644
--- a/content/strings/Zfunc.h
+++ b/content/strings/Zfunc.h
@@ -9,13 +9,11 @@
 
 vi Z(const string& S) {
 	vi z(sz(S));
-	int l = -1, r = -1;
+	int l = 0, r = 0;
 	rep(i,1,sz(S)) {
-		z[i] = i >= r ? 0 : min(r - i, z[i - l]);
+		z[i] = min(max(r - i, 0), z[i - l]);
 		while (i + z[i] < sz(S) && S[i + z[i]] == S[z[i]])
-			z[i]++;
-		if (i + z[i] > r)
-			l = i, r = i + z[i];
+			z[i]++, l = i, r = i + z[i];
 	}
 	return z;
 }