q.append((newX, newY))

return matrix

Go through the solution once again

Go through the solution once again ✅

Algo1 repeat

class Solution:

def updateMatrix(self, matrix: List[List[int]]) -> List[List[int]]:

q = deque()

for i in range(len(matrix)):

for j in range(len(matrix[0])):

if matrix[i][j] == 0:

q.append((i, j))

else:

matrix[i][j] = '#' # marked as unvisited

while q:

x, y = q.popleft()

for r, c in [(1, 0), (-1, 0), (0, 1), (0, -1)]:

newX, newY = x+r, y+c

if 0 <= newX < len(matrix) and 0 <= newY < len(matrix[0]) and matrix[newX][newY] == '#':

matrix[newX][newY] = matrix[x][y] + 1

q.append((newX, newY))

return matrix

# if we run bfs from whenever we incounter 1 then the time complexity will be 1 * O(n * m)