Lee Algorithm for Shortest Path

from collections import deque

def lee_algorithm(grid, src, dest):
    if not grid or not grid[0]:
        return -1

    rows, cols = len(grid), len(grid[0])
    visited = [[False] * cols for _ in range(rows)]
    queue = deque([(src, 0)])
    visited[src[0]][src[1]] = True

    row_num = [-1, 0, 0, 1]
    col_num = [0, -1, 1, 0]

    while queue:
        (pt, dist) = queue.popleft()

        if pt == dest:
            return dist

        for i in range(4):
            row = pt[0] + row_num[i]
            col = pt[1] + col_num[i]

            if (row >= 0 and row < rows and col >= 0 and col < cols and
                    grid[row][col] == 1 and not visited[row][col]):
                visited[row][col] = True
                queue.append(((row, col), dist + 1))

    return -1  # Destination not reachable