int (Node<?> n, int blackCount, int pathBlackCount) { if (isBlack(n)) { blackCount++; } if (n == null) { if (pathBlackCount == -1) { pathBlackCount = blackCount; } else { assert blackCount == pathBlackCount; } return pathBlackCount; } pathBlackCount = verifyProperty5Helper(n.getLeft(), blackCount, pathBlackCount); pathBlackCount = verifyProperty5Helper(n.getRight(), blackCount, pathBlackCount); return pathBlackCount; }