Answer:
Informed search (heuristic search) uses additional knowledge (heuristics) to guide search more efficiently.
A heuristic function h(n)
estimates the cost from node n
to the goal.
Greedy Best-First Search:
- Selects node with the lowest
h(n)
. - Fast but not always optimal.
- Can get stuck in local minima.

A* Search:
- Uses evaluation function:
f(n) = g(n) + h(n)
g(n)
is cost so far,h(n)
is estimated cost to goal.
- Optimal and complete if
h(n)
is admissible (never overestimates).
Example Heuristics:
- For 8-puzzle:
h₁
: number of misplaced tiles.h₂
: Manhattan distance (sum of row and column differences).
A* search is efficient and widely used in AI applications
