ex03

1. a heuristic function h(n): a heuristic value of n, that is the estimated cost of reaching goal from n. 

2. How to design heuristics?

properties of a good heuristic function should have:

• admissibility: a heuristic function is said to be admissible if it never overestimates the cost of reaching the goal, i.e. the cost it estimates to reach the goal is not higher than the lowest possible cost from the current point in the path.^[1]
• consistent: a heuristic function is said to be consistent, or monotone, if its estimate is always less than or equal to the estimated distance from any neighbouring vertex to the goal, plus the cost of reaching that neighbour.

Supplementary knowledge:

1. Admissible heuristic; consistent heuristic;