内核编译执行make menuconfig时出现的问题

一开始的问题是这样的
HOSTCC scripts/basic/fixdep
*

• Unable to find the ncurses package.
• Install ncurses (ncurses-devel or libncurses-dev
• depending on your distribution). * scripts/kconfig/Makefile:208: recipe for target 'scripts/kconfig/mconf-cfg' failed make[1]: *** [scripts/kconfig/mconf-cfg] Error 1 Makefile:552: recipe for target 'menuconfig' failed make: *** [menuconfig] Error 2

后来在百度上找到的办法是缺少ncurses的库，需要输入apt-get install libncurses5-de安装缺缺少失的库。然后问题变成了

root@ubuntu:/home/electronic/kernel/linux-5.1.10# make menuconfig UPD scripts/kconfig/mconf-cfg
HOSTCC scripts/kconfig/mconf.o
HOSTCC scripts/kconfig/lxdialog/checklist.o
HOSTCC scripts/kconfig/lxdialog/inputbox.o
HOSTCC scripts/kconfig/lxdialog/menubox.o
HOSTCC scripts/kconfig/lxdialog/textbox.o
HOSTCC scripts/kconfig/lxdialog/util.o
HOSTCC scripts/kconfig/lxdialog/yesno.o
HOSTCC scripts/kconfig/confdata.o
HOSTCC scripts/kconfig/expr.o
LEX scripts/kconfig/lexer.lex.c
/bin/sh: 1: flex: not found
scripts/Makefile.lib:194: recipe for target 'scripts/kconfig/lexer.lex.c' failed
make[1]: *** [scripts/kconfig/lexer.lex.c] Error 127
Makefile:552: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2

    然后再百度的解决方法是apt-get install bison -y，问题又是这样

LEX scripts/kconfig/lexer.lex.c
/bin/sh: 1: flex: not found
scripts/Makefile.lib:194: recipe for target 'scripts/kconfig/lexer.lex.c' failed
make[1]: *** [scripts/kconfig/lexer.lex.c] Error 127
Makefile:552: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2

之后也没有其他的解决方法。
作为一个初学linux的大学生，搞不懂，看着头疼。求大佬指点

执行下这个。

sudo apt-get install flex

你都编译内核了，还是初学？？？？？