package question;

import java.util.LinkedList;
import java.util.Queue;

/*
    @author: Roderland
    @create: 2020-08-16---15:35
*/
public class Question513 {
    public int findBottomLeftValue(TreeNode root) {
        return fun(root, depth(root));
    }
    public int depth(TreeNode root) {
        if (root==null) return 0;
        return 1+Math.max(depth(root.left), depth(root.right));
    }
    public int fun(TreeNode root, int depth) {
        if (root==null) return -1;
        if (depth==1) return root.val;
        int l = fun(root.left, depth-1);
        int r = fun(root.right, depth-1);
        if (l!=-1) return l;
        return r;
    }

    public static void main(String[] args) {
        //[1,2,3,4,null,5,6,null,null,7]
        TreeNode t1 = new TreeNode(1);
        TreeNode t2 = new TreeNode(2);
        TreeNode t3 = new TreeNode(3);
        TreeNode t4 = new TreeNode(4);
        TreeNode t5 = new TreeNode(5);
        TreeNode t6 = new TreeNode(6);
        TreeNode t7 = new TreeNode(7);
        t1.left=t2;
        t1.right=t3;
        t2.left=t4;
        t3.left=t5;
        t3.right=t6;
        t5.left=t7;
        System.out.println(new Question513().findBottomLeftValue2(t1));
    }

    //solution2
    public int findBottomLeftValue2(TreeNode root) {
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        TreeNode cur = root;
        while (!queue.isEmpty()) {
            cur = queue.peek();
            int length = queue.size();
            for (int i = 0; i < length; i++) {
                TreeNode pop = queue.poll();
                if (pop.left!=null) queue.offer(pop.left);
                if (pop.right!=null) queue.offer(pop.right);
            }
        }
        return cur.val;
    }
}