980.Unique Paths III
980. Unique Paths III
題目描述
You are given an m x n
integer array grid
where grid[i][j]
could be:
1
representing the starting square. There is exactly one starting square.
2
representing the ending square. There is exactly one ending square.
0
representing empty squares we can walk over.
-1
representing obstacles that we cannot walk over.
Return the number of 4-directional walks from the starting square to the ending square, that walk over every non-obstacle square exactly once.
範例
Example 1:
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- The image file may be corrupted
- The server hosting the image is unavailable
- The image path is incorrect
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Input: grid = [[1,0,0,0],[0,0,0,0],[0,0,2,-1]]
Output: 2
Explanation: We have the following two paths:
1. (0,0),(0,1),(0,2),(0,3),(1,3),(1,2),(1,1),(1,0),(2,0),(2,1),(2,2)
2. (0,0),(1,0),(2,0),(2,1),(1,1),(0,1),(0,2),(0,3),(1,3),(1,2),(2,2)
Example 2:
Image Not Showing
Possible Reasons
- The image file may be corrupted
- The server hosting the image is unavailable
- The image path is incorrect
- The image format is not supported
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Input: grid = [[1,0,0,0],[0,0,0,0],[0,0,0,2]]
Output: 4
Explanation: We have the following four paths:
1. (0,0),(0,1),(0,2),(0,3),(1,3),(1,2),(1,1),(1,0),(2,0),(2,1),(2,2),(2,3)
2. (0,0),(0,1),(1,1),(1,0),(2,0),(2,1),(2,2),(1,2),(0,2),(0,3),(1,3),(2,3)
3. (0,0),(1,0),(2,0),(2,1),(2,2),(1,2),(1,1),(0,1),(0,2),(0,3),(1,3),(2,3)
4. (0,0),(1,0),(2,0),(2,1),(1,1),(0,1),(0,2),(0,3),(1,3),(1,2),(2,2),(2,3)
Example 3:
Image Not Showing
Possible Reasons
- The image file may be corrupted
- The server hosting the image is unavailable
- The image path is incorrect
- The image format is not supported
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Constraints:
m
== grid.length
n
== grid[i].length
- 1 <=
m
, n
<= 20
- 1 <=
m
* n
<= 20
- -1 <=
grid[i][j]
<= 2
- There is exactly one starting cell and one ending cell.
解答
玉山
Javascript
暴力解超級慢,不知道是不是題目想要的,但暫時沒想到更好的做法。
MarsgoatFeb 22, 2023
Reference
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