시간 제한 | 메모리 제한 | 제출 | 정답 | 맞힌 사람 | 정답 비율 |
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2 초 | 512 MB | 100 | 44 | 37 | 45.679% |
A graph is made up of a set of nodes and a set of links. A link connects two nodes. For example, Figure 1 shows a simple graph with 4 nodes and 5 links. In the figure, each link has a specific direction, going from the originating node to the destination node. Each link has a cost attached to it. The m nodes of a graph are identified by the integers 0, 1, ..., m − 1.
A path connects one node to another, following the direction of links from node to node. The length of a path is the number of links used. The cost of a path is the sum of link cost over the entire path. For a given graph, your task is to find the minimum cost among the costs of all the shortest paths between Node 0 and Node 1. A shortest path with the minimum cost is called a minimum-cost shortest path.
Figure 1 | Figure 2 |
For example, again consider Figure 1. The shortest path from Node 0 to Node 1 is the 1-link path 0 → 1 with a path cost of 10. While there are cheaper paths: 0 → 2 → 1 and 0 → 3 → 1, they are longer (2 links). Therefore, 0 → 1 is the minimum-cost shortest path.
Consider another example, Figure 2. There are two shortest paths of length 2, the path 0 → 3 → 1 has a lower cost (cost = 4) than the path 0 → 2 → 1 (cost = 5). Another path 0 → 2 → 3 → 1 (cost = 3) is cheaper but longer. Therefore, the minimum-cost shortest path is 0 → 3 → 1.
The first line contains two integers m and n separated by a space, where m is the number of nodes and n is the number of links. The links of the graph and their costs are given by the next n lines. Each line has three integers (with a space between two adjacent integers), denoting Source-Node Destination-Node Link-Cost.
There are at most 100 nodes, and nodes are numbered from 0 to 99. There are at most 1000 links and link cost varies between 0 and 215 − 1.
The output file contains a single integer which is the path cost of a minimum-cost shortest path from Node 0 to Node 1.
Note that while there may be multiple minimum-cost shortest paths, the cost of these paths are the same.
4 5 0 2 2 0 3 2 0 1 10 2 1 2 3 1 2
10