Exercise 2: Get Neighbors of a Node 🔍

Your Task

Write a function get_neighbors(num_nodes, edges, x) that:

1. Builds an adjacency list from the given edge list
2. Returns the list of direct neighbors of node x (nodes that x points to)

The graph is directed — edge [u, v] means there's an arrow from u to v.

---

Examples

print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 0))
# Output: [1, 2]

print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 1))
# Output: [3]

print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 3))
# Output: []

print(get_neighbors(3, [[0,1], [1,2], [2,0]], 2))
# Output: [0]

---

Expected Complexity

	Complexity
Time	O(V + E)
Space	O(V + E)

Where V is the number of nodes and E is the number of edges.

Why? Building the adjacency list takes O(V + E). Looking up neighbors is O(1).

---

Approach

1. Build the adjacency list (same as Exercise 1)
2. Return adj[x]

---

Starter Code

def get_neighbors(num_nodes, edges, x):
    # Your code here
    pass

# Test your function:
print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 0))
# Output: [1, 2]

print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 1))
# Output: [3]

print(get_neighbors(4, [[0,1], [0,2], [1,3], [2,3]], 3))
# Output: []

print(get_neighbors(3, [[0,1], [1,2], [2,0]], 2))
# Output: [0]

print(get_neighbors(5, [[0,1], [0,4], [1,2], [1,3]], 0))
# Output: [1, 4]

---

Hints