隐马尔可夫模型，C语言编写，重要的是里面附带有隐马尔可夫模型原理介绍的ppt，可以对应学习-HMM, C language, it is important that they are incidental tenets of Hidden Markov Models introduced ppt, can learn from counterparts

fft算法的例子代码以及fft相关知识的ppt，其中fft算法是用C语言实现的，且做了很详细的注释。- fft algorithms fft ppt example code and related knowledge, where fft algorithm is implemented in C, and made a very detailed notes.