Create 1091-shortest-path-in-a-binary-matrix.py

Author: neetcode-gh

python/1091-shortest-path-in-a-binary-matrix.py

@@ -0,0 +1,19 @@
+class Solution:
+    def shortestPathBinaryMatrix(self, grid: List[List[int]]) -> int:
+        N = len(grid)
+        q = deque([(0, 0, 1)]) # r, c, length
+        visit = set((0, 0))
+        direct = [[0, 1], [1, 0], [0, -1], [-1, 0],
+                  [1, 1], [-1, -1], [1, -1], [-1, 1]]
+        while q:
+            r, c, length = q.popleft()
+            if (min(r, c) < 0 or max(r, c) >= N or
+                grid[r][c]):
+                continue
+            if r == N - 1 and c == N - 1:
+                return length
+            for dr, dc in direct:
+                if (r + dr, c + dc) not in visit:
+                    q.append((r + dr, c + dc, length + 1))
+                    visit.add((r + dr, c + dc))
+        return -1