MediumNo. 0361LeetCode Premium
Bomb Enemy — LeetCode 361 Python Solution
- Pattern
- Matrix and Grid
- Topics
- Array, Dynamic Programming, Matrix
- Reading time
- 7 min
- Source
- leetcode.com
The problem
Given an m x n matrix grid where each cell is either a wall 'W', an enemy 'E' or empty '0', return the maximum enemies you can kill using one bomb. You can only place the bomb in an empty cell.
Example
- Input
- grid = [["0","E","0","0"],["E","0","W","E"],["0","E","0","0"]]
- Output
- 3
Python solution
class Solution:
def maxKilledEnemies(self, grid: List[List[str]]) -> int:
m, n = len(grid), len(grid[0])
g = [[0] * n for _ in range(m)]
for i in range(m):
t = 0
for j in range(n):
if grid[i][j] == 'W':
t = 0
elif grid[i][j] == 'E':
t += 1
g[i][j] += t
t = 0
for j in range(n - 1, -1, -1):
if grid[i][j] == 'W':
t = 0
elif grid[i][j] == 'E':
t += 1
g[i][j] += t
for j in range(n):
t = 0
for i in range(m):
if grid[i][j] == 'W':
t = 0
elif grid[i][j] == 'E':
t += 1
g[i][j] += t
t = 0
for i in range(m - 1, -1, -1):
if grid[i][j] == 'W':
t = 0
elif grid[i][j] == 'E':
t += 1
g[i][j] += t
return max(
[g[i][j] for i in range(m) for j in range(n) if grid[i][j] == '0'],
default=0,
)Complexity
- Time
- O(n·m) (typical)
- Space · auxiliary
- O(n·m)or optimized
Pattern: Matrix and Grid
Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 361. Bomb Enemy is filed here because LeetCode tags it Matrix, which is the vocabulary this hub collects.
The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 0063 | Unique Paths II | Medium |
| 0064 | Minimum Path Sum | Medium |
| 0085 | Maximal Rectangle | Hard |
| 0174 | Dungeon Game | Hard |
| 0221 | Maximal Square | Medium |
| 0329 | Longest Increasing Path in a Matrix | Hard |
Frequently asked questions
- How hard is LeetCode 361. Bomb Enemy?
LeetCode 361. Bomb Enemy is rated Medium on LeetCode.
- What topics does LeetCode 361. Bomb Enemy cover?
LeetCode 361. Bomb Enemy is tagged Array, Dynamic Programming and Matrix on LeetCode.
- Is LeetCode 361. Bomb Enemy a premium problem?
Yes. LeetCode 361. Bomb Enemy is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.