Suppose P is the shortest path from a starting node s to a destination node v in a graph G. Suppose also that G' is G with all edge weights modified by multiplying a constant factor C > 0.Then P (with the corresponding edge weight modifications) is also the shortest path between s and v in the modified graph G'.
Question
Suppose P is the shortest path from a starting node s to a destination node v in a graph G. Suppose also that G' is G with all edge weights modified by multiplying a constant factor C > 0.Then P (with the corresponding edge weight modifications) is also the shortest path between s and v in the modified graph G'.
Solution
Yes, the statement is correct. The shortest path from node s to node v in graph G will remain the same in the modified graph G' even after all edge weights are multiplied by a constant factor C > 0. This is because multiplying all edge weights by a constant factor does not change the relative weights of the edges. Therefore, the shortest path in G will still have the smallest total weight in G', preserving the property of the shortest path.
Here are the steps to understand this:
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Let's say the shortest path P in graph G from s to v is through nodes s, a, b, ..., v with weights w1, w2, ..., wn respectively. So, the total weight of path P is w1 + w2 + ... + wn.
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Now, in the modified graph G', the weights of the edges in path P become Cw1, Cw2, ..., Cwn. So, the total weight of path P in G' is Cw1 + Cw2 + ... + Cwn = C * (w1 + w2 + ... + wn).
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As you can see, the total weight of path P in G' is just the total weight of path P in G multiplied by the constant factor C.
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Since all edge weights in G' are multiplied by the same constant factor C, the relative weights of the edges remain the same. Therefore, if path P was the shortest path in G, it will still be the shortest path in G' because its total weight is still the smallest.
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Hence, the statement is correct.
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