加深加廣
https://cp.wiwiho.me/convex-hull/
https://hackmd.io/@yjk930805/share#%E5%AF%A6%E6%88%B0
https://hackmd.io/@nckuacm/ryLIV6BYI/%2F%40nckuacm%2FBJD15vyrI
https://hackmd.io/@sa072686/APCS_HARD/https%3A%2F%2Fhackmd.io%2Fs%2FSknKMqIQ7
https://tioj.ck.tp.edu.tw/articles/5