答案1
像这样：
\usepackage{fancyhdr}
\pagestyle{fancy}
\lhead{\parbox{\columnwidth}{\thepage \hfill foo}}
\rhead{\parbox{\columnwidth}{foo\hfill\thepage}}
LaTeX：在两列页面上显示两个标题
像这样：
\usepackage{fancyhdr}
\pagestyle{fancy}
\lhead{\parbox{\columnwidth}{\thepage \hfill foo}}
\rhead{\parbox{\columnwidth}{foo\hfill\thepage}}