摘要：LCA 资料: http://www.cnblogs.com/zgmf_x20a/archive/2008/10/15/1311313.html虽然网上这方面资料很多了， 不过自己练习后还是写下。。。POJ1330NearestCommonAncestors输入N-1条边，建一个树，然后是一个LCA查询，只有一次，朴素做比较快。树是唯一的。POJ1470ClosestCommonAncestors和上一题非常类似，不过点变少了，查询次数变多了，因为n<=900朴素就可以了。POJ1986DistanceQueries查询从u-v的距离。根据输入建一个树，以任意点位根都可以，距离是不变的。 阅读全文

摘要：The city of Thunder has many houses and they are powered by lightning. Two houses may be interconnected by a wire. The wires connect the houses such that there is exactly one path from one house to any other house in the city. Each house has a large battery that can store infinite electrical energy. 阅读全文