Reference article:
take you step by step to install the most difficult VIM plug-in in history: youcompleteme
VIM plug-in: minimalist VIM plug-in manager

Installation method

install VIM
sudo apt get install VIM edit vimrc
first add VIM ~ /. Vimrc
at the top:
call plug#begin (‘~ /. VIM/plugged’)
plug ‘valloric/youcompleteme’
call plug#end() to install VIM plug and install youcompleteme through plugged

Input: curl – flo ~ /. VIM/autoload at the terminal/ plug.vim –create-dirs https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim Open VIM
Enter “: source ~ /. Vimrc” at the command line
Enter “: pluginstall” at the command line to install youcompleteme, which takes a long time. Please wait patiently for YCM to be compiled and installed_ core
mkdir ~/.ycm_ build
cd ~/.ycm_ build
cmake -G “Unix Makefiles” . ~/.vim/plugged/YouCompleteMe/third_ party/ycmd/cpp
cmake –build . –target ycm_ core –config Release

Supplement: VIM prompts the debugging method of the ycmd server shut down:

Select log through ycmtogglelogs to view errors

For example, the solution of no module named watchdog: PIP3 install watchdog