原创 POJ 1741 Tree [樹上點分治]
類似的還有POJ 1987 題意：給出一棵樹，問樹上點對<A,B>所代表的簡單路徑長度<=K的不同點對數。 解法：樹分治經典題了，求重心分治後，dfs求當前子樹所有點到重心的距離，將求得的距離排序，用指針掃描法O（N）統計路徑長度<=K的
2018-08-22 05:28:33
2
原创 UVALive 6900 Road Repair [樹分治+線段樹]
題意：有一棵樹，樹上每條邊都有其花費和收益，找一條簡單路徑，使花費在<=C的情況下，收益最大，輸出最大收益。 解法：對於尋找路徑的問題，可以考慮樹分治，分治之後，需要考慮經過當前重心的路徑是否可能是答案，那麼統計其所有兒子到當前重心的花費
2018-08-22 05:28:33
2
原创 BZOJ 4016 最短路徑樹問題 [最短路+樹分治]
Description 給一個包含n個點，m條邊的無向連通圖。從頂點1出發，往其餘所有點分別走一次並返回。 往某一個點走時，選擇總長度最短的路徑走。若有多條長度最短的路徑，則選擇經過的頂點序列字典序最小的那條路徑(如路徑A爲1,3
2018-08-22 05:28:33
3
原创 SPOJ QTREE Query on a tree [樹鏈剖分+線段樹]
Description You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3..
2018-08-22 05:28:33
1
原创 HDU 4812 D Tree [樹分治]
Description There is a skyscraping tree standing on the playground of Nanjing University of Science and Technology.
2018-08-22 05:28:33
4
原创 HDU 3271 SNIBB[數位DP]
Description As we know, some numbers have interesting property. For example, any even number has the property that
2018-08-22 05:28:33
原创 ZOJ 3640 Help Me Escape [概率DP]
Description Now Cain is unexpectedly trapped in a cave with N paths. Due to LORD's punishment, all the paths are zig
2018-08-22 05:28:32