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RegionsCutBySlashes.py
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RegionsCutBySlashes.py
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class Solution:
def regionsBySlashes(self, grid: List[str]) -> int:
'''
dfs - ac
represent each grid as a 3x3 matrix:
backslash = [
[0,0,1],
[0,1,0],
[1,0,0]
]
slash = [
[1,0,0],
[0,1,0],
[0,0,1]
]
then perform a dfs similar to number of islands
'''
def dfs(x,y):
if not 0<=x<length*3 or not 0<=y<length*3 or g[x][y] != 0:
return
g[x][y] = 2
dfs(x+1,y)
dfs(x,y+1)
dfs(x-1,y)
dfs(x,y-1)
return
def append_to(a,b):
a[0] += b[0]
a[1] += b[1]
a[2] += b[2]
return a
length = len(grid)
g = []
backslash = [
[0,0,1],
[0,1,0],
[1,0,0]
]
slash = [
[1,0,0],
[0,1,0],
[0,0,1]
]
blank = [
[0,0,0],
[0,0,0],
[0,0,0]
]
for i in range(length):
curr = [[],[],[]]
for j in range(length):
if grid[i][j] == '/':
curr = append_to(curr,backslash)
elif grid[i][j] == '\\':
curr = append_to(curr,slash)
else:
curr = append_to(curr,blank)
for k in curr:
g.append(k)
count = 0
for i in range(length*3):
for j in range(length*3):
if g[i][j] == 0:
dfs(i,j)
count += 1
return count