hdu 5.3.4 2874 Connextions between cities

最新推荐文章于 2016-07-26 11:53:55 发布

shshwdr

最新推荐文章于 2016-07-26 11:53:55 发布

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分类专栏： acm 文章标签： each path output query input c

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本文探讨在世界大战后城市重建过程中，如何利用给定的交通道路信息，解决城市间是否存在路径及最短路径查询的问题。通过实例分析，展示了通过普通并查集算法解决此类问题的高效性和实用性。

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lca是啥？rmq又是啥？咋又突然变成并查集的东东了咧？不是吧我树状数组还半懂不懂完全不懂啊！

Connections between cities

Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)

Total Submission(s): 168 Accepted Submission(s): 52

Problem Description

After World War X, a lot of cities have been seriously damaged, and we need to rebuild those cities. However, some materials needed can only be produced in certain places. So we need to transport these materials from city to city. For most of roads had been totally destroyed during the war, there might be no path between two cities, no circle exists as well.
Now, your task comes. After giving you the condition of the roads, we want to know if there exists a path between any two cities. If the answer is yes, output the shortest path between them.

Input

Input consists of multiple problem instances.For each instance, first line contains three integers n, m and c, 2<=n<=10000, 0<=m<10000, 1<=c<=1000000. n represents the number of cities numbered from 1 to n. Following m lines, each line has three integers i, j and k, represent a road between city i and city j, with length k. Last c lines, two integers i, j each line, indicates a query of city i and city j.

Output

For each problem instance, one line for each query. If no path between two cities, output “Not connected”, otherwise output the length of the shortest path between them.

Sample Input