摘要：B. Jzzhu and Cities http://codeforces.com/contest/449/problem/B 题意：给出n个点m条公路k条铁路。 接下来m行 u v w u->v 距离w 然后k行 v w 1->v 距离w 如果修建了铁路并不影响两点的最短距离，那么修铁路是没必要的 阅读全文

摘要：Fight Against Traffic Little town Nsk consists of n junctions connected by m bidirectional roads. Each road connects two distinct junctions and no two 阅读全文

摘要：A Walk Through the Forest Jimmy experiences a lot of stress at work these days, especially since his accident made working difficult. To relax after a 阅读全文