Array ( [0] => Array ( [title] => L18A [link] => https://www.youtube.com/embed/_5vcrqwxduc ) [1] => Array ( [title] => L18B [link] => https://www.youtube.com/embed/zfWJONgaf_k ) [2] => Array ( [title] => L18C [link] => https://www.youtube.com/embed/yaykieg-eiw ) [3] => Array ( [title] => L18D [link] => https://www.youtube.com/embed/_vJq5R_J6EI ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第18R講 Example of Pigeohole Principle