使用COM组件，检测url是否有效，客户程序调用com组件，vc测试通过，其他的语言未测试-The use of COM components, testing url is valid, the customer calls com components, vc test is passed, other languages are not testing

Constrained LCS. Given two sequences X, Y and a constrained sequence P, a sequence Z is a constrained longest common subsequence for X and Y with respect to P if Z is the longest subsequence of X and Y such that P is a subsequence of Z.