Proceedings of Practice of Interesting Algorithms 2007 The editor assumes no responsibility for the accuracy, completeness or usefulness of the information disclosed in this volume. Unauthorized use might infringe on privately owned patents of publication right. Please contact the individual authors for permission to reprint or otherwise use information from their papers. First edition 2007 Publication Planned by Prof. Wenxin Li Edited by Yili Zhao All rights reserved by Artificial Intelligence Laboratory, Peking University June 26, 2007
