小鸡的小车

2005年11月

Problem Statement

When editing a single line of text, there are four keys that can be used to move the cursor: end, home, left-arrow and right-arrow. As you would expect, left-arrow and right-arrow move the cursor one character left or one character right, unless the cursor is at the beginning of the line or the end of the line, respectively, in which case the keystrokes do nothing (the cursor does not wrap to the previous or next line). The home key moves the cursor to the beginning of the line, and the end key moves the cursor to the end of the line. You will be given a int, N, representing the number of character in a line of text. The cursor is always between two adjacent characters, at the beginning of the line, or at the end of the line. It starts before the first character, at position 0. The position after the last character on the line is position N. You should simulate a series of keystrokes and return the final position of the cursor. You will be given a string where characters of the string represent the keystrokes made, in order. 'L' and 'R' represent left and right, while 'H' and 'E' represent home and end.
Definition

Class:
CursorPosition
Method:
getPosition
Parameters:
string, int
Returns:
int
Method signature:
int getPosition(string keystrokes, int N)
(be sure your method is public)

Constraints
-
keystrokes will be contain between 1 and 50 'L', 'R', 'H', and 'E' characters, inclusive.
-
N will be between 1 and 100, inclusive.
Examples
0)

"ERLLL"
10
Returns: 7
First, we go to the end of the line at position 10. Then, the right-arrow does nothing because we are already at the end of the line. Finally, three left-arrows brings us to position 7.
1)

"EHHEEHLLLLRRRRRR"
2
Returns: 2
All the right-arrows at the end ensure that we end up at the end of the line.
2)

"ELLLELLRRRRLRLRLLLRLLLRLLLLRLLRRRL"
10
Returns: 3

"RRLEERLLLLRLLRLRRRLRLRLRLRLLLLL"
19
Returns: 12

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.

我的程序：

#include <string>
#include <iostream>

using namespace std;

class CursorPosition
{
public:
int getPosition(string keystrokes, int N)
{
  int result = 0;
  size_t len = keystrokes.length();
  if (len>50 || N<1 || N>100)
  {
   return result;
  }
  for (unsigned int i=0; i<len; ++i)
  {
   switch(keystrokes.at(i))
   {
   case 'L':
    result = result==0 ? 0 : result-1;
    break;
   case 'R':
    result = result==N ? N : result+1;
    break;
   case 'H':
    result = 0;
    break;
   case 'E':
    result = N;
    break;
   }
  }
  return result;
}
};

发表于 @ 2005年11月24日 11:58 AM | 评论 (0)

Google™ Code Jam - 中国编程挑战赛500分练习题

Problem Statement

A square matrix is a grid of NxN numbers. For example, the following is a 3x3 matrix:
4 3 5
2 4 5
0 1 9
One way to represent a matrix of numbers, each of which is between 0 and 9 inclusive, is as a row-major string. To generate the string, simply concatenate all of the elements from the first row followed by the second row and so on, without any spaces. For example, the above matrix would be represented as "435245019". You will be given a square matrix as a row-major string. Your task is to convert it into a vector <string>, where each element represents one row of the original matrix. Element i of the vector <string> represents row i of the matrix. You should not include any spaces in your return. Hence, for the above string, you would return {"435","245","019"}. If the input does not represent a square matrix because the number of characters is not a perfect square, return an empty vector <string>, {}.
Definition

Class:
MatrixTool
Method:
convert
Parameters:
string
Returns:
vector <string>
Method signature:
vector <string> convert(string s)
(be sure your method is public)

Constraints
-
s will contain between 1 and 50 digits, inclusive.
Examples
0)

"435245019"
Returns: {"435", "245", "019" }
The example above.
1)

"9"
Returns: {"9" }

"0123456789"
Returns: { }
This input has 10 digits, and 10 is not a perfect square.
3)

"3357002966366183191503444273807479559869883303524"
Returns: {"3357002", "9663661", "8319150", "3444273", "8074795", "5986988", "3303524" }

我的程序：

#include <algorithm>
#include <string>
#include <vector>
#include <iostream>

using namespace std;

class MatrixTool
{
public:
vector<string > convert(string s)
{
  int sqt[7] = {1, 4, 9, 16, 25, 36, 49};
  vector<string > result;
  int* p = find(sqt, sqt + 7, s.length());
  if (p != sqt + 7)
  {
   unsigned int n = (unsigned int)(p - sqt) + 1;
   size_t len = s.length();
   for (unsigned int i=0; i<len; i+=n)
   {
    result.push_back(s.substr(i, n));
   }
  }
  return result;
}
};

发表于 @ 2005年11月24日 11:57 AM | 评论 (0)

Google™ Code Jam - 中国编程挑战赛250分练习题

摘要：

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 vector <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 pix （全文共11119字）——点击此处阅读全文

发表于 @ 2005年11月24日 11:56 AM | 评论 (0)

星球大战

摘要：

著名的ASCII动画。

观看方法：telnet towel.blinkenlights.nl

（全文共59字）——点击此处阅读全文

发表于 @ 2005年11月21日 2:51 PM | 评论 (1)

拿着鸡毛当令箭

摘要：北航保安（全文共494字）——点击此处阅读全文

发表于 @ 2005年11月12日 11:06 PM | 评论 (0)

健身，健身

摘要：