GEN-HUEY CHENKao, Ming-YangMing-YangKaoYUH-DAUH LYUUWong, Hsing-KuoHsing-KuoWong2020-05-042020-05-04200107349025https://scholars.lib.ntu.edu.tw/handle/123456789/488228https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032663830&doi=10.1145%2f301250.301284&partnerID=40&md5=8418f4c06f2b96122d93f8b99b198fe9A general solution is presented for any finite request-answer game to derive its optimal competitive ratio and optimal randomized on-line algorithm against the oblivious adversary. The solution is based on game theory. We then apply the framework to the practical buy-and-hold trading problem and find the exact optimal competitive ratio and an optimal randomized on-line algorithm. We also prove the uniqueness of the solution.Computational complexity; Game theory; Optimization; Random processes; Theorem proving; Buy-and-hold trading; Finite request-answer games; Randomized on-line algorithms; Algorithmsjournal article10.1137/S00975397993588472-s2.0-0032663830https://doi.org/10.1137/S0097539799358847