Top Coder挑战赛

https://www.topcoder.com/pl/?module=Static&d1=gccj05&d2=ZH_overview

今天注册进去玩了一把,比赛还没正式开始,现在里面只提供practice
room让大家练习用。先从最简单的开始，做了一个250分的题，用Java做的，我好久没写Java了，题目虽简单，我却生疏了，编译了N次才过，调测
试用例也废了好长时间，最后成功提交了，只得了八十多分。看看排行榜，竟然有249.99分的大牛，惭愧不已阿。

开始还不知道到底评分系统怎么工作的，然后又进了practice room，还是选了个250分的题，还是上次那道阿，把上道题的代码copy
& paste进去，compile &
submit，呵呵，248.xx分，原来评分系统只看你提交的速度而已。好了，再进一个再选250，以迅雷不及掩耳盗铃之势，paste,
compile & submit，249.99分产生了。惭愧之意顿去，高分如此而已。

哪天有空再去看看500分/1000分的题，反正已经有人做出来了，应该不会太难吧，呵呵。

我把250分的题放在这里，呵呵，有兴趣参加的朋友先做出来，跑过了测试用例再去不迟，要拿高分，paste & compile & submit动作一定要快啊

做题目默认用Java写，不过好像也可以用C++/C#还有VB

—————————————————————————————————-
Problem Statement

A simple
line drawing program uses a blank 20 x 20 pixel canvas and a
directional cursor that starts at the upper left corner pointing
straight down. The upper left corner of the canvas is at (0, 0) and the
lower right corner is at (19, 19). You are given a String[], commands,
each element of which contains one of two possible commands. A command
of the form "FORWARD x" means that the cursor should move forward by x
pixels. Each pixel on its path, including the start and end points, is
painted black. The only other command is "LEFT", which means that the
cursor should change its direction by 90 degrees counterclockwise. So,
if the cursor is initially pointing straight down and it receives a
single "LEFT" command, it will end up pointing straight to the right.
Execute all the commands in order and return the resulting 20 x 20
pixel canvas as a String[] where character j of element i represents
the pixel at (i, j). Black pixels should be represented as uppercase
‘X’ characters and blank pixels should be represented as ‘.’ characters.

Definition

Class: DrawLines

Method: execute

Parameters: String[]

Returns: String[]

Method signature: String[] execute(String[] commands)

(be sure your method is public)

Notes

– The cursor only paints the canvas if it moves (see example 1). Constraints

– commands will contain between 1 and 50 elements, inclusive.

– Each
element of commands will be formatted as either "LEFT" or "FORWARD x"
(quotes for clarity only), where x is an integer between 1 and 19,
inclusive, with no extra leading zeros.

– When executing the commands in order, the cursor will never leave the 20 x 20 pixel canvas.

Examples

0) {"FORWARD 19", "LEFT", "FORWARD 19", "LEFT", "FORWARD 19", "LEFT", "FORWARD 19"}

Returns:

{"XXXXXXXXXXXXXXXXXXXX",

"X………………X",

"XXXXXXXXXXXXXXXXXXXX" }

This sequence of commands draws a 20 x 20 outline of a square. The
cursor is initially at (0, 0) pointing straight down. It then travels
to (0, 19) after the first FORWARD command, painting each pixel along
its path with a ‘*’. It then rotates 90 degrees left, travels to (19,
19), rotates 90 degrees left, travels to (19, 0), rotates 90 degrees
left, and finally travels back to (0, 0).

1) {"LEFT", "LEFT", "LEFT", "LEFT", "LEFT", "LEFT", "LEFT", "LEFT"}

Returns:

{"………………..",

"………………..",

"……………….." }

The cursor spins round and round, but never actually paints any pixels. The result is an empty canvas.

2){"FORWARD 1"}

Returns:

{"X……………….",

"X……………….",

"………………..",

"……………….." }

Going forward by one pixel creates a line that is 2 pixels long because both the start and end points are painted.

3) {"LEFT", "FORWARD 19", "LEFT", "LEFT", "LEFT",

"FORWARD 18", "LEFT", "LEFT", "LEFT", "FORWARD 17",

"LEFT", "LEFT", "LEFT", "FORWARD 16", "LEFT",

"LEFT", "LEFT", "FORWARD 15", "LEFT", "LEFT", "LEFT",

"FORWARD 14", "LEFT", "LEFT", "LEFT", "FORWARD 13",

"LEFT", "LEFT", "LEFT", "FORWARD 12", "LEFT", "LEFT",

"LEFT", "FORWARD 11", "LEFT", "LEFT", "LEFT", "FORWARD 10",

"LEFT", "LEFT", "LEFT", "FORWARD 9", "LEFT", "LEFT",

"LEFT", "FORWARD 8", "LEFT", "LEFT", "LEFT", "FORWARD 7"}

Returns:

{"XXXXXXXXXXXXXXXXXXXX",

"……………….X",

"..XXXXXXXXXXXXXXXX.X",

"..X…………..X.X",

"..X.XXXXXXXXXXXX.X.X",

"..X.X……….X.X.X",

"..X.X.XXXXXXXX.X.X.X",

"..X.X.X……..X.X.X",

"..X.X.XXXXXXXXXX.X.X",

"..X.X…………X.X",

"..X.XXXXXXXXXXXXXX.X",

"..X…………….X",

"..XXXXXXXXXXXXXXXXXX",

"……………….." }

This
problem statement is the exclusive and proprietary property of
TopCoder, Inc. Any unauthorized use or reproduction of this information
without the prior written consent of TopCoder, Inc. is strictly
prohibited. (c)2003, TopCoder, Inc. All rights reserved.

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