In artificial intelligence (AI), search algorithms are essential for solving a variety of problems, from navigating a maze to scheduling tasks. Uninformed search, also known as blind search, is a fundamental category of search techniques where the algorithm has no additional information about the states beyond what is provided in the problem definition to guide the search. This page delves into the basics of uninformed search algorithms, their types, and their applications in AI.
Types of Uninformed Search Algorithms
1. Breadth-First Search (BFS)
How it works: BFS explores all nodes at the present depth level before moving on to nodes at the next depth level. It uses a queue to keep track of the frontier, ensuring that the shallowest nodes are expanded first.
Applications: BFS is particularly useful in scenarios where the shortest path is needed in terms of the number of edges traversed, such as in unweighted graph problems.
2. Depth-First Search (DFS)
How it works: DFS
explores as far down a branch as possible before backtracking. It uses a stack
(either explicitly or through recursion) to keep track of the path.
Applications: DFS
is often used in scenarios where solutions are deep in the search tree, such as
puzzles or games with many possible moves.
3. Uniform Cost Search (UCS)
How it works: UCS
expands the least-cost node first. It uses a priority queue to ensure nodes are
expanded in order of their path cost from the start node.
Applications: UCS
is ideal for finding the least-cost solution in scenarios where costs vary
between actions, such as routing problems.
4. Depth-Limited Search (DLS)
How it works: DLS
operates like DFS but with a predetermined limit on the depth of exploration.
This prevents the search from going infinitely deep.
Applications: DLS
is useful when the search space is large, and a solution is expected to be
found within a certain depth.
5. Iterative Deepening Search (IDS)
How it works: IDS
combines the benefits of BFS and DFS by performing a series of depth-limited
searches with increasing depth limits. It effectively finds the shallowest goal
state without requiring large memory overhead.
Applications: IDS
is often used in scenarios like those for BFS, particularly when the depth of
the solution is unknown.