=== Segment Tree ===
 * 자료
  * http://codeforces.com/blog/entry/18051
  * http://codeforces.com/blog/entry/15890
 * 문제
  * http://codeforces.com/contest/380/problem/C

=== 기하 ===
 * 문제
  * http://codeforces.com/contest/614/problem/C
   * http://www.ahristov.com/tutorial/geometry-games/point-line-distance.html

=== KMP ===
 * 자료
  * http://carstart.tistory.com/143
  * http://www.inf.fh-flensburg.de/lang/algorithmen/pattern/kmpen.htm
  * https://www.youtube.com/watch?v=HaAu5ZGj6fc
 * 문제
  * http://codeforces.com/contest/471/problem/D (다른 풀이를 통해 nlogn으로 풀 수도 있으나 KMP로 n만에 풀이 가능)