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KOICOST - Cost |
You are given an undirected graph with N vertices and M edges, where the weights are unique.
There is a function Cost(u, v), which is defined as follows:
While there is a path between vertex u and v, delete the edge with the smallest weight. Cost(u,v) is the sum of the weights of the edges that were deleted in this process.
For example, from the graph above (same as the sample input), Cost(2,6) is 2+3+4+5+6 = 20.
Given an undirected graph, your task is to calculate the sum of Cost(u,v) for all vertices u and v, where u < v. Since the answer can get large, output the answer modulo 10^9.
Input
The first line of the input consists of two integers, N and M. (1 <= N <= 100,000, 0 <= M <= 100,000)
The next M lines consists of three integers, u, v, and w. This means that there is an edge between vertex u and v with weight w. (1 <= u, v <= N, 1 <= w <= 100,000)
Output
Output the sum specified in the problem statement.
Example
Input: 6 7
1 2 10
2 3 2
4 3 5
6 3 15
3 5 4
4 5 3
2 6 6 Output: 256
Added by: | Lawl |
Date: | 2011-06-01 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | 2011 KOI Regional |
hide comments
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2017-10-09 07:39:19
Can someone explain me the sample test case? I can only see 2 path to 2->6 in the sample input . that are 1. direct edge 2->6 2. 2->3->6 |
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2017-06-20 11:02:44
Getting WA on case 20 even with modulo 10^9 :( |
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2017-01-28 04:18:01
if getting wa on case 20 ,becauz mode = 1000000000 not 10e9+7 it's good question try to think reverse , instead of deleting ,join and instead of min. wt start from max wt :) |
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2017-01-05 22:57:06 Wumbolo
According to the Merriam-Webster dictionary entry for vertex, vertices and vertexes can be used as the plural of vertex, so verticies is *wrong*. |
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2016-12-14 08:53:20
why i got wa on test20?sad :< |
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2016-12-08 17:04:07
best problem of dsu on spoj ............. |
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2016-05-25 06:51:41 cosmopoliton
got a wa bcz of this incomplete input statement :(. |
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2016-03-21 23:55:11 Augusto
Statement is incomplete :/ you need to print the answer modulo 10^9 thanks for the modulo @Rajat De :) |
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2016-03-18 23:56:46
don't use vector . it causes a segment fault |
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2016-02-04 13:49:37 Liquid_Science
seems to get NZEC in java ,are the constraints correctly specified? |