Searching is the universal technique of problem solving in AI. There are some single-player games such as tile games, Sudoku, crossword, etc. The search algorithms help you to search for a particular position in such games.

Single Agent Pathfinding Problems

The games such as 3X3 eight-tile, 4X4 fifteen-tile, and 5X5 twenty four tile puzzles are single-agent-path-finding challenges. They consist of a matrix of tiles with a blank tile. The player is required to arrange the tiles by sliding a tile either vertically or horizontally into a blank space with the aim of accomplishing some objective.

The other examples of single agent pathfinding problems are Travelling Salesman Problem, Rubik’s Cube, and Theorem Proving.

Search Terminology

· Problem Space − It is the environment in which the search takes place. (A set of states and set of operators to change those states)

· Problem Instance − It is Initial state + Goal state.

· Problem Space Graph − It represents problem state. States are shown by nodes and operators are shown by edges.

· Depth of a problem − Length of a shortest path or shortest sequence of operators from Initial State to goal state.

· Space Complexity − The maximum number of nodes that are stored in memory.

· Time Complexity − The maximum number of nodes that are created.

· Admissibility − A property of an algorithm to always find an optimal solution.

· Branching Factor − The average number of child nodes in the problem space graph.

· Depth − Length of the shortest path from initial state to goal state.

Brute-Force Search Strategies

They are most simple, as they do not need any domain-specific knowledge. They work fine with small number of possible states.

Requirements −

• State description

• A set of valid operators

• Initial state

• Goal state description