Java simple solution

  • 0
    public List<String> binaryTreePaths(TreeNode root) {
        List<String> paths = new ArrayList<>();
        binaryTreePaths(root, paths, new StringBuilder());
        return paths;
    public void binaryTreePaths(TreeNode root, List<String> paths, StringBuilder builder) {
        if(root == null) return;
        if(root.left == null && root.right == null) paths.add(builder.append("->").append(root.val).substring(2));
        if(root.left != null) binaryTreePaths(root.left, paths, new StringBuilder(builder.toString()));
        if(root.right != null) binaryTreePaths(root.right, paths, new StringBuilder(builder.toString()));

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