题目网址 list下标是从0开始的
[]是列表
()是元组
{}是集合
python变量的指向和引用
a+=a是修改a的值，其地址没变；a=a+a地址变了
主要考察的还是python的基本数据结构的使用，参考的代码和教程是这个 LeetCode版
class Solution:
def floodFill(self, image, sr, sc, newColor):
m = len(image)
n = len(image[0])
directions = [(-1,0),(1,0),(0,-1),(0,+1)]
visited = {(sr, sc)}
same_color = image[sr][sc]
to_check = [(sr, sc)]
while to_check:
center_r,center_c = to_check.pop()
visited.add((center_r,center_c))
image[center_r][center_c] = newColor
# add 4 directionally connected pixels
for r,c in directions:
if 0<=center_r+r<m and 0<=center_c+c<n and (center_r+r,center_c+c) not in visited and image[center_r+r][center_c+c]==same_color:
to_check.append((center_r+r,center_c+c))
return image
S=Solution()
image = [[1,1,1],[1,1,0],[1,0,1]]
sr = 1
sc = 1
newColor = 2
new_image=S.floodFill(image,sr,sc,newColor)
print(new_image)
image = [[0, 0, 0], [0, 0, 0]]
sr = 0
sc = 0
newColor = 2
new_image=S.floodFill(image,sr,sc,newColor)
print(new_image)结果，可见还有提高的空间
pycharm版：
class Solution:
def floodFill(self, image, sr, sc, newColor):
m = len(image)
n = len(image[0])
directions = [(-1,0),(1,0),(0,-1),(0,+1)]
visited = {(sr, sc)}
same_color = image[sr][sc]
to_check = [(sr, sc)]
while to_check:
center_r,center_c = to_check.pop()
visited.add((center_r,center_c))
image[center_r][center_c] = newColor
# add 4 directionally connected pixels
for r,c in directions:
if 0<=center_r+r<m and 0<=center_c+c<n and (center_r+r,center_c+c) not in visited and image[center_r+r][center_c+c]==same_color:
to_check.append((center_r+r,center_c+c))
return image
S=Solution()
image = [[1,1,1],[1,1,0],[1,0,1]]
sr = 1
sc = 1
newColor = 2
new_image=S.floodFill(image,sr,sc,newColor)
print(new_image)
image = [[0, 0, 0], [0, 0, 0]]
sr = 0
sc = 0
newColor = 2
new_image=S.floodFill(image,sr,sc,newColor)
print(new_image)
