src/problems/iprb.lisp @ 892a16d8007e
TRIE
author |
Steve Losh <steve@stevelosh.com> |
date |
Sat, 18 Jan 2020 14:03:44 -0500 |
parents |
474d88a2af2e |
children |
2735aa6aab79 |
(in-package :rosalind)
(define-problem iprb (data stream)
"2 2 2"
"0.78333"
(let* ((d (read data))
(h (read data))
(r (read data))
(n (+ d h r)))
;; We could expand this all into a giant equation and cancel it out, but
;; let's just let the computer do the busywork.
(flet ((p-same (x also-x)
(declare (ignore also-x))
;; P({X X}) = X/N * (X-1)/(N-1)
;; = X(X-1) / N(N-1)
;; = X²-X / N²-N
(/ (- (* x x) x)
(- (* n n) n)))
(p-diff (x y)
;; P({X Y}) = P(X, Y) + P(Y, X)
;; = X/N * Y/N-1 + Y/N * X/N-1
;; = XY/N(N-1) + YX/N(N-1)
;; = 2XY/N(N-1)
;; = 2XY/N²-N
(/ (* 2 x y)
(- (* n n) n))))
(float-string
(+ (* (p-same d d) 1) ;; AA AA
(* (p-diff d h) 1) ;; AA Aa
(* (p-diff d r) 1) ;; AA aa
(* (p-same h h) 3/4) ;; Aa Aa
(* (p-diff h r) 1/2) ;; Aa aa
(* (p-same r r) 0))
5)))) ;; aa aa
;; (problem-iprb)
;; (solve iprb)