AI · Theory

Iterative Deepening A* Algorithm (IDA*)

Theory

125/215

Iterative Deepening A* Algorithm (IDA*)

Iterative Deepening A* Algorithm (IDA*) is a search strategy. Say the data structure, whether it uses a heuristic, and if it guarantees a shortest path. Draw a tiny 6-node graph. That is the exam, not a textbook proof.

Iterative Deepening A* Algorithm (IDA*) — output: three exam lines. Graph on paper first.

For Iterative Deepening A* Algorithm (IDA*): always mark visited nodes or you loop. Say complexity in plain words: time vs memory trade-off.

Diagram

f(n) = g(n) + h(n)
  pick smallest f
  admissible h → optimal

Exam tip

DS + heuristic yes/no + optimality.

Example

# Iterative Deepening A* Algorithm (IDA*)
print("draw 6 nodes")
print("name the DS: queue / stack / priority")
print("say if the path is optimal")

Iterative Deepening A* Algorithm (IDA*) — output: three exam lines. Graph on paper first.

Short notes

DefIterative Deepening A* Algorithm (IDA*) — how we walk the state graph.
RuleIterative Deepening A* Algorithm (IDA*) — visited set.
RememberIterative Deepening A* Algorithm (IDA*) — heuristic or not?

AI · Theory

Iterative Deepening A* Algorithm (IDA*)

← All stacks

Theory

125/215

Iterative Deepening A* Algorithm (IDA*)

Iterative Deepening A* Algorithm (IDA*) — output: three exam lines. Graph on paper first.

For Iterative Deepening A* Algorithm (IDA*): always mark visited nodes or you loop. Say complexity in plain words: time vs memory trade-off.

Diagram

f(n) = g(n) + h(n)
  pick smallest f
  admissible h → optimal

Exam tip

DS + heuristic yes/no + optimality.

Example

# Iterative Deepening A* Algorithm (IDA*)
print("draw 6 nodes")
print("name the DS: queue / stack / priority")
print("say if the path is optimal")

Iterative Deepening A* Algorithm (IDA*) — output: three exam lines. Graph on paper first.

Short notes

DefIterative Deepening A* Algorithm (IDA*) — how we walk the state graph.
RuleIterative Deepening A* Algorithm (IDA*) — visited set.
RememberIterative Deepening A* Algorithm (IDA*) — heuristic or not?

Iterative Deepening A* Algorithm (IDA*)

Example

Short notes

Questions

Iterative Deepening A* Algorithm (IDA*)

Example

Short notes

Questions