algorithm2e格式紧凑 有竖线，若想用algorithm2e一般模版已经定义过algorithm 会报错

Since the algorithm and algorithm2e packages both define an algorithm environment, simply loading both with no extra precaution will cause a name clash like you experienced.

However, you can still use both packages (if you really need both), but you need to pass the option algo2e to algorithm:

\usepackage[algo2e]{algorithm2e}