From 44fa83f03350a57c4a944c58274691f38347c995 Mon Sep 17 00:00:00 2001
From: shironeko <shironeko@tesaguri.club>
Date: Sun, 15 Nov 2020 17:45:12 +0800
Subject: [PATCH] use vectors

---
 lotte-cli.scm  | 12 ++++++------
 lotte/main.scm | 51 ++++++++++++++++++++++----------------------------
 2 files changed, 28 insertions(+), 35 deletions(-)

diff --git a/lotte-cli.scm b/lotte-cli.scm
index dfef3b5..5a2d493 100755
--- a/lotte-cli.scm
+++ b/lotte-cli.scm
@@ -49,12 +49,12 @@
   (iter '()))
 
 (define (print-winners winners)
-  (if (not (null? winners))
-      (let ((winner (car winners)))
-        (if (not (null? winner))
-            (begin
-              (format #t "~A score: ~A\n" (car winner) (cdr winner))
-              (print-winners (cdr winners)))))))
+  (define (iter i)
+    (if (< i (vector-length winners))
+        (let ((winner (vector-ref winners i)))
+          (format #t "~A score: ~A\n" (car winner) (cdr winner))
+          (iter (1+ i)))))
+  (iter 0))
 
 (define opt (cdr (command-line)))
 (call-with-input-file
diff --git a/lotte/main.scm b/lotte/main.scm
index fb49eac..34f54e8 100644
--- a/lotte/main.scm
+++ b/lotte/main.scm
@@ -23,36 +23,29 @@
 (define (lotte lotte-name lucky-num num-of-winners users)
   ; User's score is the smallest value obtained by
   ; hash(num from 1 to lucky-num + ' ' + lotte-name + ' ' + username)
-  (define (get-score user)
+  (define (score-user user)
     (define (iter num score)
       (if (zero? num)
           score
-          (iter (1- num) (string-min score (hash-strs (number->string num)
-                                                      lotte-name user)))))
-    (iter lucky-num max-score))
-  (define (iter winners-rev len users-left)
-    ; Insert new winner into the list sorted from highest to lowest
-    (define (insert-winner winner winners-rev)
-      (define (iter winners winners-left)
-        (if (null? winners-left)
-            (reverse (cons winner winners))
-            (if (string<? (cdr winner) (cdar winners-left))
-                (iter (cons (car winners-left) winners) (cdr winners-left))
-                (append (reverse winners) (cons winner winners-left)))))
-      (iter '() winners-rev))
+          (iter (1- num)
+                (string-min (hash-strs (number->string num) lotte-name user)
+                            score))))
+    (cons user (iter lucky-num max-score)))
+  (define (iter winners users-left)
+    ; Insert user into the winners list sorted from lowest to highest if they
+    ; score smaller than any of them
+    (define (insert-user! user)
+      (define (iter i)
+        (if (< i (vector-length winners))
+            (if (string<? (cdr user) (cdr (vector-ref winners i)))
+                (begin (vector-move-right!
+                         winners i (1- (vector-length winners))
+                         winners (1+ i))
+                       (vector-set! winners i user))
+                (iter (1+ i)))))
+      (iter 0))
     (if (null? users-left)
-        (reverse winners-rev)
-        (let* ((user (car users-left))
-               (score (get-score user)))
-          (if (< len num-of-winners)
-              (iter (insert-winner (cons user score) winners-rev)
-                    (1+ len)
-                    (cdr users-left))
-              (if (string<? score (cdar winners-rev))
-                  (iter (insert-winner (cons user score) (cdr winners-rev))
-                        len
-                        (cdr users-left))
-                  (iter winners-rev len (cdr users-left)))))))
-  (let* ((user (car users))
-         (score (get-score user)))
-    (iter (list (cons user score)) 1 (cdr users))))
+        winners
+        (begin (insert-user! (score-user (car users-left)))
+               (iter winners (cdr users-left)))))
+  (iter (make-vector num-of-winners (cons "" max-score)) users))
-- 
2.45.2