This study investigates the tree structure reconstruction problem of general rooted trees, focusing on whether the original tree structure can be uniquely reconstructed using only Depth-First Search (DFS) and Breadth-First Search (BFS) sequences. An O(n) algorithm implemented in C++ is proposed, and the source of non-uniqueness is identified as the so-called Traversal Isomorphic Block (TIB). To resolve this ambiguity, the reversed Depth-First Search (DFS⁻) is introduced as an additional condition. The results show that the combination of the three sequences (DFS, BFS, DFS⁻) enables the unique reconstruction of the original tree in O(n) time, forming a practical linear-time reconstruction framework and clarifying the ambiguities inherent in DFS and BFS.