The Lowest Common Ancestor (LCA) problem is very important in applications such as computing the LCA of classes in an inheritance hierarchy in the implementation of object-oriented programming systems, or applications related to computational biology. In this project, I implemented a faster algorithm for answering the lowest common ancestor queries in O(1) time complexity with O(n) preprocessing time complexity. I also showed the result of testing for different kinds of large trees and their corresponding running time in the report.