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General Computer Science 320201 GenCS I & II Lecture ... - Kwarc

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Note: Equivalent to breadth-first search if all step costs are equal (DFS: see below)<br />

Sibiu<br />

140<br />

Arad<br />

Uniform Cost Search: Romania<br />

118<br />

Idea: Expand least-cost unexpanded node<br />

75<br />

Timisoara<br />

c○: Michael Kohlhase 438<br />

71<br />

Oradea<br />

Zerind<br />

Implementation: fringe is queue ordered by increasing path cost.<br />

Note: Equivalent to breadth-first search if all step costs are equal (DFS: see below)<br />

Sibiu<br />

140<br />

Arad<br />

Uniform Cost Search: Romania<br />

118<br />

Idea: Expand least-cost unexpanded node<br />

118<br />

Arad<br />

75<br />

Timisoara<br />

Lugoj<br />

c○: Michael Kohlhase 439<br />

111<br />

71<br />

Oradea<br />

75<br />

Zerind<br />

Implementation: fringe is queue ordered by increasing path cost.<br />

Note: Equivalent to breadth-first search if all step costs are equal (DFS: see below)<br />

Arad<br />

140<br />

Fagaras<br />

99<br />

Sibiu<br />

151<br />

Oradea<br />

140<br />

80<br />

R. Vilcea<br />

Arad<br />

118<br />

118<br />

Arad<br />

75<br />

Timisoara<br />

Lugoj<br />

c○: Michael Kohlhase 440<br />

111<br />

75<br />

71<br />

Oradea<br />

Arad<br />

Arad<br />

Zerind<br />

Note that we must sum the distances to each leaf. That is, we go back to the first level after step<br />

3.<br />

Uniform-cost search: Properties<br />

Complete Yes (if step costs ≥ ɛ > 0)<br />

Time number of nodes with past-cost less than that of optimal solution<br />

Space number of nodes with past-cost less than that of optimal solution<br />

Optimal Yes<br />

244<br />

75<br />

Arad

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