Map of Highest Peak — LeetCode 1765 Python Solution
MediumBreadth-First SearchArrayMatrix
- Problem
- #1765
- Pattern
- Matrix and Grid
- Reading time
- 3 min
- Source
- leetcode.com
The problem
You are given an integer matrix isWater of size m x n that represents a map of land and water cells. If isWater[i][j] == 0, cell (i, j) is a land cell.
Example
- Input
- isWater = [[0,1],[0,0]]
- Output
- [[1,0],[2,1]]
- Explanation
- The image shows the assigned heights of each cell.
Python solution
Python
class Solution:
def highestPeak(self, isWater: List[List[int]]) -> List[List[int]]:
m, n = len(isWater), len(isWater[0])
ans = [[-1] * n for _ in range(m)]
q = deque()
for i, row in enumerate(isWater):
for j, v in enumerate(row):
if v:
q.append((i, j))
ans[i][j] = 0
while q:
i, j = q.popleft()
for a, b in pairwise((-1, 0, 1, 0, -1)):
x, y = i + a, j + b
if 0 <= x < m and 0 <= y < n and ans[x][y] == -1:
ans[x][y] = ans[i][j] + 1
q.append((x, y))
return ansComplexity
| Measure | Complexity |
|---|---|
| Time | O(V+E) |
| Space | O(V) auxiliary |
Pattern: Matrix and Grid
Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 1765. Map of Highest Peak 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
Frequently asked questions
- How hard is LeetCode 1765. Map of Highest Peak?
- LeetCode 1765. Map of Highest Peak is rated Medium on LeetCode.
- What is the time complexity of LeetCode 1765. Map of Highest Peak?
- The Python solution on this page runs in O(V+E).
- What is the space complexity of LeetCode 1765. Map of Highest Peak?
- The Python solution on this page uses O(V) auxiliary space.
- What topics does LeetCode 1765. Map of Highest Peak cover?
- LeetCode 1765. Map of Highest Peak is tagged Breadth-First Search, Array and Matrix on LeetCode.