BFS implementation in 2D space

Programs/bfs_2D.py

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+# Program to do bfs in 2-d matrix assuming you are provided wioth the start node and the
+# only directions you can travel is up down left and right
+
+from collections import deque
+
+print("Enter size of the matrix:")
+n, m = map(int, input().split())
+visited = [[0 for i in range(m)] for i in range(n)]
+
+# keeping track of every node from the root node
+dist = [[0 for i in range(m)] for i in range(n)]
+
+
+def isValid(node_x, node_y):
+
+    if 0 <= node_x <= n-1 and 0 <= node_y <= m-1:
+        if visited[node_x][node_y] == 0:
+            return True
+    else:
+        return False
+
+
+# level order traversal with respect to the root node
+def bfs(root_x, root_y):
+    visited[root_x][root_y] = 1
+
+    q = deque()
+    q.append([root_x, root_y])
+
+    # up,right,down,left
+    dx = [-1, 0, 1, 0]
+    dy = [0, 1, 0, -1]
+
+    while len(q) > 0:
+        node = q.popleft()
+        for i in range(len(dx)):
+            new_x = node[0] + dx[i]  
+            new_y = node[1] + dy[i]  
+            if isValid(new_x, new_y):
+                visited[new_x][new_y] = 1
+                # distance of child node = distance of parent node + 1
+                dist[new_x][new_y] = dist[node[0]][node[1]] + 1
+                # append the new nodes to the queue
+                q.append([new_x, new_y])
+
+print("Enter which node you want to act as the root node")
+node, y = map(int, input().split())
+bfs(node, y)
+
+for i in range(0, n):
+    print(" ".join(str(j) for j in dist[i][0:]))
+