From 1b62a1a2041bfab4e126ec4299c5328c69febaf4 Mon Sep 17 00:00:00 2001
From: pimgeek <wudi.biz@gmail.com>
Date: Wed, 4 Jun 2014 01:57:56 +0800
Subject: [PATCH] Update ahead_one_step.md
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

提供一个 racket 5.2.1 的解法
---
 ahead_one_step.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/ahead_one_step.md b/ahead_one_step.md
index 77cbe93..cc8a65b 100644
--- a/ahead_one_step.md
+++ b/ahead_one_step.md
@@ -18,3 +18,19 @@
 	
 	if __name__ =="__main__":
 	    print ahead_one()
+
+#解决(racket 5.2.1)
+
+```racket
+#lang racket
+
+; 定义函数 ahead-one
+; 输入为一个整数列表 int-list，假设其长度为 N
+; 输出为长度相同的整数列表，其第 N 位的元素为 int-list 的第 1 位的元素，
+; 其 1~N-1 位的元素为 int-list 的第 2~N 位的元素
+(define (ahead-one int-list)
+  (append (rest int-list) (list (first int-list))))
+
+; 函数调用，正常运行时应输出 '(2 3 4 5 6 7 8 9 10 1)
+(ahead-one (list 1 2 3 4 5 6 7 8 9 10))
+```