package LeetCode;

import java.util.ArrayList;
import java.util.List;

public class LC_257 {
    public static void main(String[] args) {

    }

    public static List<String> binaryTreePaths(TreeNode root) {
        ArrayList<String> res = new ArrayList<>();
        ArrayList<Integer> path = new ArrayList<>();
        if (root == null) return res;
        traversal(root, path, res);
        return res;
    }

    public static void traversal(TreeNode cur, ArrayList<Integer> path, ArrayList<String> res) {
        path.add(cur.val);
        if (cur.left == null && cur.right == null) {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < path.size() - 1; i++) sb.append(path.get(i)).append("->");
            sb.append(path.get(path.size() - 1));
            res.add(sb.toString());
            return;
        }
        if (cur.left != null) {
            traversal(cur.left, path, res);
            path.remove(path.size() - 1);
        }
        if (cur.right != null){
            traversal(cur.right, path, res);
            path.remove(path.size() - 1);
        }
    }
}