One year is enough. College mathematics is simpler than high school mathematics. Many people want to know why, because there are few things at the core of high school mathematics, but the topics are full of tricks, which makes you feel that you will never give up until you die. After learning many powerful new tools in college mathematics, many problems can be easily solved, mainly by understanding the principles and tools. After understanding them, it is simple (unlike high school mathematics, understanding principles can be deadly). . . This is the same as when I didn't learn equations in primary school. It is actually very difficult to do some application problems (including now, it is sometimes very difficult to solve primary school mathematics without equations), but it is a truth that I will be so relaxed after learning equations. . .
College mathematics is basically calculus, linear algebra and probability, which are actually very powerful mathematical tools. I recommend you to go to Netease open class and learn a set of Stanford courseware, one-dimensional calculus, multivariate calculus and linear algebra. . . Then Harvard probability statistics. . . It's easy to understand, and it's simpler than what Mr. China said (because even in Stanford and Harvard, their students' math foundation is very general, just listen to their questions), but it's enough. . . Sometimes people can see the big picture. . .