Determine the Left View of a Binary Tree

You are given a binary tree of integers. Your task is to determine the left view of the binary tree. The left view consists of nodes that are visible when the tree is viewed from the left side.

Example:

Input:

T = 1
Binary Tree Level Order Input: 1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1

Output:

1 2 4 7

Explanation:

The left view of the binary tree is 1, 2, 4, 7 as shown in the image below:

Constraints:

1

Question

Determine the Left View of a Binary Tree

You are given a binary tree of integers. Your task is to determine the left view of the binary tree. The left view consists of nodes that are visible when the tree is viewed from the left side.

Example:

Input:

T = 1
Binary Tree Level Order Input: 1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1

Output:

1 2 4 7

Explanation:

The left view of the binary tree is 1, 2, 4, 7 as shown in the image below:

example image

Constraints:

1 <= T <= 100
0 <= N <= 3000
1 <= data <= 10⁵ and data ≠ -1

Note:

You do not need to handle any input/output operations; just implement the function to return the required result.

Accepted Answer

The task is to determine the left view of a binary tree, which consists of nodes visible when viewed from the left side.

Traverse the binary tree in a level order manner and keep track of the leftmost node at each level.
Use a queue to perform level order traversal of the binary tree.
Maintain a count of nodes at each level to identify the leftmost node.
Return the leftmost nodes at each level as the left view of the binary tree.