Class Graph
Hard
There is a directed weighted graph that consists of n
nodes numbered from 0
to n - 1
. The edges of the graph are initially represented by the given array edges
where edges[i] = [fromi, toi, edgeCosti]
meaning that there is an edge from fromi
to toi
with the cost edgeCosti
.
Implement the Graph
class:
Graph(int n, int[][] edges)
initializes the object withn
nodes and the given edges.addEdge(int[] edge)
adds an edge to the list of edges whereedge = [from, to, edgeCost]
. It is guaranteed that there is no edge between the two nodes before adding this one.int shortestPath(int node1, int node2)
returns the minimum cost of a path fromnode1
tonode2
. If no path exists, return-1
. The cost of a path is the sum of the costs of the edges in the path.
Example 1:
Input [“Graph”, “shortestPath”, “shortestPath”, “addEdge”, “shortestPath”] [[4, [[0, 2, 5], [0, 1, 2], [1, 2, 1], [3, 0, 3]]], [3, 2], [0, 3], 1, 3, 4, [0, 3]]
Output: [null, 6, -1, null, 6]
Explanation:
Graph g = new Graph(4, [[0, 2, 5], [0, 1, 2], [1, 2, 1], [3, 0, 3]]);
g.shortestPath(3, 2); // return 6. The shortest path from 3 to 2 in the first diagram above is 3 -> 0 -> 1 -> 2 with a total cost of 3 + 2 + 1 = 6.
g.shortestPath(0, 3); // return -1. There is no path from 0 to 3.
g.addEdge([1, 3, 4]); // We add an edge from node 1 to node 3, and we get the second diagram above.
g.shortestPath(0, 3); // return 6. The shortest path from 0 to 3 now is 0 -> 1 -> 3 with a total cost of 2 + 4 = 6.
Constraints:
1 <= n <= 100
0 <= edges.length <= n * (n - 1)
edges[i].length == edge.length == 3
0 <= fromi, toi, from, to, node1, node2 <= n - 1
1 <= edgeCosti, edgeCost <= 106
- There are no repeated edges and no self-loops in the graph at any point.
- At most
100
calls will be made foraddEdge
. - At most
100
calls will be made forshortestPath
.
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
addEdge
(int[] edge) int
shortestPath
(int node1, int node2) Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Constructor Details
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Graph
public Graph(int n, int[][] edges)
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Method Details
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addEdge
public void addEdge(int[] edge) -
shortestPath
public int shortestPath(int node1, int node2)
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