Uninformed Search and Heuristic Search Notes for GATE DA: Concepts, Formulas, Worked Examples & Practice

    Uninformed Search and Heuristic Search notes for GATE DA: 23 study cards covering concepts, formulas, shortcuts and exam traps, plus solved practice questions.

    Chapter Roadmap: Search Strategies in AI

    Chapter Journey: From Blind Search to Smart Search

    TOPIC 1: Uninformed Search (Current)

    BFS, DFS & Strategy Classification

    Learn how computers explore state spaces blindly. Understand the trade-offs between Breadth-First and Depth-First search.

    Weightage Hint: High Foundation
    TOPIC 2: Heuristic Search (Next)

    A* Search & Admissible Heuristics

    Introduce smart guesses, called heuristics, to guide search. Master the A-star algorithm and the concept of admissibility.

    What you will master in this topic:
    1. The mechanics of BFS and DFS.
    2. How to classify search strategies based on completeness, optimality, time, and space.
    3. Solving complex tracing questions on state expansion with custom constraints.

    The Search Problem: States, Actions, and Goals

    Defining the Search Space

    To solve any problem using search, we need four components:

    1. Initial State: Where you start ().
    2. Actions: What moves are available? For a state , returns possible moves.
    3. Transition Model: Where do you end up? gives the new state after action .
    4. Goal Test: Is this the solution? returns true or false.
    The State Space Graph
    • Nodes: Represent states.
    • Edges: Represent actions with costs.
    • Path: A sequence of states from start to goal.
    Key Insight: Search algorithms differ only in which node they choose to expand next.

    Uninformed vs. Informed Search

    Classification of Search Strategies

    Feature Uninformed (Blind) Search Informed (Heuristic) Search
    Knowledge Only knows legal moves Knows estimated distance to goal
    Efficiency Often slow, explores heavily Faster, directed towards goal
    Examples BFS, DFS, Uniform Cost A*, Greedy Best-First
    Use Case Small spaces, no heuristic available Large spaces, good heuristic exists
    Why study Uninformed Search?

    It forms the baseline. If you do not have a good heuristic, or if the space is small, these are your only options. They are also complete and optimal under specific conditions.

    Breadth-First Search (BFS): The Layer-by-Layer Explorer

    Breadth-First Search (BFS)

    Breadth-First Search is like dropping a stone in water. The ripples expand outward layer by layer.

    Strategy

    Expand the shallowest unexpanded node.

    Data Structure

    FIFO Queue (Frontier).

    Algorithm Steps

    1. Add start node to the queue.
    2. While queue is not empty:
      • Remove the front node ().
      • If is the goal, return success.
      • Otherwise, add all children of to the back of the queue.
    Visualizing the Order:
    Note: BFS guarantees that if a solution exists, it will find the one with the fewest steps (shortest path in terms of edges).

    More notes in this unit

    chapter
    Uninformed Search and Heuristic Search Notes for GATE DA: Concepts, Formulas, Worked Examples & Practice

    Uninformed Search and Heuristic Search notes for GATE DA: 23 study cards covering concepts, formulas, shortcuts and exam traps, plus solved practice questions

    Free preview ends here

    Login to view the complete notes

    Creating an account is free. You get the rest of this chapter, step-by-step solutions, and a study plan built around the topics you are actually weak at.

    Login to continueSee plans
    Why MastersUp

    Personalised first. High quality throughout.

    Most platforms hand everyone the same content. Here the content moves with your performance, topic by topic.

    Built around you, not around a syllabus PDF

    Every answer you give moves your topic-level intelligence rate. The next question, the next revision card and tomorrow's plan all change with it.

    Revision that hits your weak spots

    We only revise topics you have actually attempted and are still below the safe bar on — never the same chapter on repeat.

    Questions calibrated to the real exam

    Each question carries a measured toughness. You are served a rung above your current level, so practice keeps stretching you.

    Notes written for recall, not for volume

    Full lesson cards for first study, curated short-note cards for the last mile — with derivations, traps and exam patterns marked.

    One place for everything

    Notes, chapter practice, previous-year questions, test series and full-length papers — all feeding one picture of your preparation.

    Honest progress

    No vanity streaks. Progress here means chapters mastered and accuracy that held up on harder questions.

    Unlock the whole course

    Full notes and short notes, the complete question bank with worked solutions, mock tests, full-length papers, and an adaptive plan that rebuilds itself as you improve.

    View all plansStart free