常用LaTeX格式
0.字体
<font face="黑体" > </font>
1.多行对齐

\begin{align*}\label{2} & f[i][j]=f[i-1][j-1]+1\\ & f[i][j]=f[i-1][j]+1 \end{align*}
2.空格

3.分类%3D%0A%5Cbegin%7Bcases%7D%20%0An%2F2%2C%20%26%20%5Ctext%20%7Bif%20%24n%24%20is%20even%7D%20%5C%5C%20%0A3n%2B1%2C%20%26%20%5Ctext%7Bif%20%24n%24%20is%20odd%7D%20%0A%5Cend%7Bcases%7D "图片标题")
f(n)= \begin{cases} n/2, \text {if $n$ is even} \\ 3n+1, \text{if $n$ is odd} \end{cases}