 In particular, we first provide a (\frac{1}{2}-\varepsilon) -approximation algorithm that requires O(\frac{1}{\varepsilon} \cdot \log \frac{k}{\varepsilon}) passes over the stream for any constant \varepsilon>0 . In addition, we design a single-pass streaming algorithm that has the same  (\frac{1}{2}-\varepsilon) approximation ratio when unlimited buffer size and post-processing time is permitted\emph{ \emph{ .
<meaning-changed>  In particular, we first provide a (\frac{1}{2}-\varepsilon) -approximation algorithm that requires O(\frac{1}{\varepsilon} \cdot \log \frac{k}{\varepsilon}) passes over the stream for any constant \varepsilon>0 . In addition, we design a single-pass streaming algorithm that has the same  (\frac{1}{2}-\varepsilon) approximation ratio when unlimited buffer size and post-processing time is permitted\emph{ \emph{ .
 In particular, we first provide a (\frac{1}{2}-\varepsilon) -approximation algorithm that requires O(\frac{1}{\varepsilon} \cdot \log \frac{k}{\varepsilon}) passes over the stream for any constant \varepsilon>0 . In addition, we design a single-pass streaming algorithm that has the same (\frac{1}{2}-\varepsilon) approximation ratio when unlimited buffer size and post-processing time are permitted, and discuss how to adapt it to more practical settings where the buffer sizes are bounded. Finally, we demonstrate the efficiency and effectiveness of our proposed algorithms on two real-world applications, namely\emph{ \emph{ .