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Update matrix_dfs_and_bfs.py

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bt3gl 2023-08-08 16:21:22 -07:00 committed by GitHub
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1 changed files with 1 additions and 20 deletions
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graphs/matrix_dfs_and_bfs.py
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@ -2,22 +2,12 @@
# -*- coding: utf-8 -*- # -*- coding: utf-8 -*-
# author: bt3gl # author: bt3gl
'''
Given an m x n 2D binary grid grid which represents a map of
'1's (land) and '0's (water), return the number of islands.
An island is surrounded by water and is formed by connecting
adjacent lands horizontally or vertically. You may assume all
four edges of the grid are all surrounded by water.
'''
def num_island_dfs(grid) -> int: def num_island_dfs(grid) -> int:
LAND = '1' LAND = '1'
answer = 0 answer = 0
#######################
### go dfs
#######################
def dfs(row, col): def dfs(row, col):
if row < 0 or row >= len(grid) or col < 0 or col >= len(grid[0]) or grid[row][col] != LAND: if row < 0 or row >= len(grid) or col < 0 or col >= len(grid[0]) or grid[row][col] != LAND:
@ -29,16 +19,12 @@ def num_island_dfs(grid) -> int:
dfs(row, col - 1) dfs(row, col - 1)
dfs(row, col + 1) dfs(row, col + 1)
#######################
## loop through the board
#######################
for i in range(len(grid)): for i in range(len(grid)):
for j in range(len(grid[0])): for j in range(len(grid[0])):
if grid[i][j] == LAND: if grid[i][j] == LAND:
answer += 1 answer += 1
dfs(i, j) dfs(i, j)
return answer return answer
@ -48,9 +34,6 @@ def num_island_bfs(grid) -> int:
answer = 0 answer = 0
queue = collections.deque() queue = collections.deque()
#######################
### go dfs
#######################
def bfs(row, col, queue): def bfs(row, col, queue):
delta = [(1, 0), (0, 1), (-1, 0), (0, -1)] delta = [(1, 0), (0, 1), (-1, 0), (0, -1)]
@ -67,9 +50,7 @@ def num_island_bfs(grid) -> int:
grid[px][py] = 'x' grid[px][py] = 'x'
queue.append((px, py)) queue.append((px, py))
#######################
## loop through the board
#######################
for i in range(len(grid)): for i in range(len(grid)):
for j in range(len(grid[0])): for j in range(len(grid[0])):