Question Definition
Given a binary tree, find the leftmost value in the last row of the tree.
Example 1:
Input:
2
/ \
1 3
Output:
1
Example 2:
Input:
1
/ \
2 3
/ / \
4 5 6
/
7
Output:
7
**Note: **You may assume the tree (i.e., the given root node) is not NULL.
Java Solution
public int findBottomLeftValue(TreeNode root) {
Queue<TreeNode> queue = new LinkedList<>();
queue.offer(root);
queue.offer(null);
int result = root.val;
while(!queue.isEmpty()){
TreeNode cur = queue.poll();
if(cur == null){
if(queue.isEmpty()) break;
queue.offer(null);
cur = queue.poll();
result = cur.val;
}
if(cur.left != null) queue.offer(cur.left);
if(cur.right != null) queue.offer(cur.right);
}
return result;
}
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