Algorithm


Q221.

What is the time complexity of Bellman-Ford single-source shortest path algorithm on a complete graph of n vertices?
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Q222.

Dijkstra's single source shortest path algorithm when run from vertex a in the above graph, computes the correct shortest path distance to
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Q223.

Let G = (V, E) be a simple undirected graph, and s be a particular vertex in it called the source. For x \in V, let d(x) denote the shortest distance in G from s to x. A breadth first search (BFS) is performed starting at s. Let T be the resultant BFS tree. If (u,v) is an edge of G that is not in T, then which one of the following CANNOT be the value of d(u)-d(v)?
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Q224.

Consider the directed graph shown in the figure below. There are multiple shortest paths between vertices S and T. Which one will be reported by Dijkstra's shortest path algorithm? Assume that, in any iteration, the shortest path to a vertex v is updated only when a strictly shorter path to v is discovered
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Q225.

Let G = (V,E) be an undirected graph with a sub-graph G1 = (V1,E1), Weight are assigned to edges of G as follows w(e)=\left\{\begin{matrix} 0 &if \; e \in E, \\ 1& otherwise \end{matrix}\right. A single-source shortest path algorithm is executed on the weighted graph (V,E,w) with an arbitrary vertex v1 of V1 as the source. Which of the following can always be inferred from the path costs computed?
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Q226.

Which of the following statement(s) is/are correct regarding Bellman-Ford shortest path algorithm? P. Always finds a negative weighted cycle, if one exists. Q. Finds whether any negative weighted cycle is reachable from the source.
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Q227.

In an unweighted, undirected connected graph, the shortest path from a node S to every other node is computed most efficiently, in terms of time complexity, by
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Q228.

Let s and t be two vertices in a undirected graph G=(V, E) having distinct positive edge weights. Let [X, Y] be a partition of V such that s\inX and t\inY. Consider the edge e having the minimum weight amongst all those edges that have one vertex in X and one vertex in Y. Let the weight of an edge e denote the congestion on that edge. The congestion on a path is defined to be the maximum of the congestions on the edges of the path. We wish to find the path from s to t having minimum congestion. Which one of the following paths is always such a path of minimum congestion?
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Q229.

Consider a complete undirected graph with vertex set {0, 1, 2, 3, 4}. Entry W_{ij} in the matrix W below is the weight of the edge {i, j}. \begin{pmatrix} 0&1 & 8 & 1 &4 \\ 1& 0 & 12 & 4 & 9\\ 8 & 12 & 0 & 7 & 3\\ 1& 4& 7 & 0 &2 \\ 4& 9 & 3& 2 &0 \end{pmatrix}What is the minimum possible weight of a path P from vertex 1 to vertex 2 in this graph such that P contains at most 3 edges?
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Q230.

Consider the weighted undirected graph with 4 vertices,where the weigh to edge {i, j} is given by the entry Wij in the matrix W. W=\begin{bmatrix} 0 & 2&8 & 5\\ 2& 0& 5 &8 \\ 8 & 5 & 0& x\\ 5&8 & x&0 \end{bmatrix} The largest possible integer value of x, for which at least one shortest path between some pair of vertices will contain the edge with weight x is ____.
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