Check if BST is valid

gistfile1.m

+ (BOOL)isBSTValid {
	return [self validate:self.root withMin:MIN.INTEGER withMax:MAX.INTEGER];
}

- (BOOL)validate:(Node *)root withMin:(NSUInteger)min withMax:(NSUInteger)max {
	
	if (root.value <= min || root.value >= max) {
		return NO;
	}

	return ([self validate:root.left withMin:min withMax:root.Value] && [self validate:root.right withMin:root.value withMax:max]);
}