We study two related problems on simple, un-directed graphs: Edge Deletion to Cactus and Spanning Tree to Cactus. Edge Deletion to Cactus has been known to be NP-hard on general graphs at least since 1988. We show improved exact algorithms for the former and a polynomial time algorithm for the latter.

翻译：我们研究简单无向图上的两个相关问题的算法：删除边形成仙人掌图和生成树形成仙人掌图。删除边形成仙人掌图问题自1988年以来就已知在一般图上是NP困难的。我们给出了针对前者的改进精确算法，以及针对后者的多项式时间算法。