# 5. Nädal

Lokaalne otsing; AIMA chapter 4.1-4.1.1.

Lühendatud slaidid: PDF

## Harjutustund

Heuristiline otsing.

Toorik koos testseisudega:

```import search

class EightPuzzle(search.Problem):
def actions(self, state):
space = state.index(0)
row = space // 3
col = space % 3

act = []
if row == 0:
act.append(state[space + 3])
elif row == 1:
act.append(state[space + 3])
act.append(state[space - 3])
elif row == 2:
act.append(state[space - 3])
if col == 0:
act.append(state[space + 1])
elif col == 1:
act.append(state[space + 1])
act.append(state[space - 1])
elif col == 2:
act.append(state[space - 1])
return act

def result(self, state, action):
newstate = list(state)
klotsi_idx = newstate.index(action)
space = newstate.index(0)
newstate[space] = action
newstate[klotsi_idx] = 0
return tuple(newstate)

def h1(self, node):
h = 0
for i in range(9):
if node.state[i] != 0:
if node.state[i] != self.goal[i]:
h += 1
return h

def h2(self, node):
rightpos = {
1 : (0, 0),
2: (0, 1),
3: (0, 2),
4: (1, 0),
5: (1, 1),
6: (1, 2),
7: (2, 0),
8: (2, 1),
}
h = 0
for i in range(9):
if node.state[i] != 0:
row = i // 3
col = i % 3
goal_row, goal_col = rightpos[node.state[i]]
h += abs(row - goal_row)
h += abs(col - goal_col)
return h

inistate = (1,2,3,7,0,5,8,4,6)
test1=(1,4,3,8,6,2,7,0,5)
test2=(2,1,8,0,4,3,7,6,5)
test3=(2,1,8,4,6,3,0,7,5)
test4=(5,7,6,4,0,8,3,2,1)
test5=(0,1,5,7,3,2,8,4,6)

goal = (1,2,3,4,5,6,7,8,0)
#problem = EightPuzzle(inistate, goal)
problem = EightPuzzle(test3, goal)

#print(problem.actions(goal))
#print(problem.result(inistate, 7))