Let G be a weighted connected undirected graph with distinct positive edge weights. If every edge weight is increased by the same value, then which of the following statements is/are TRUE? P: Minimum spanning tree of G does not change Q: Shortest path between any pair of vertices does not change
Let G be a weighted connected undirected graph with distinct positive edge weights. If every edge weight is increased by the same value, then which of the following statements is/are TRUE? P: Minimum spanning tree of G does not change Q: Shortest path between any pair of vertices does not change Correct Answer P only
Concept:
A minimum spanning tree (MST) or minimum weight spanning tree is a subset of the edges(V – 1 ) of a connected, edge-weighted undirected graph G(V, E) that connects all the vertices together, without any cycles and with the minimum possible total edge weight.
Example:
Graph G(V, E)
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Shortest path between A and C = A → B and B → C, that is,1 + 2 = 3
G(V, V – 1) → minimum spanning tree
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Increase the weight of G(V, E) by 10
Graph G'(V, E)
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Shortest path between A and C = A → C = 20 (different path)
G'(V, V – 1) → minimum spanning tree
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Statement P: TRUE
Minimum spanning the tree of G does not change
Statement Q: False
Shortest path between any pair of vertices may change