文档介绍：The 4th Collegiate Programming Contest of
Central South University
Problem Set
Hosted by School of Information Science and Engineering
April 25, 2010
This problem set contains 11 problems; pages are numbered from 1 to 19.
Problem A. Avatar
Description
In the Pandora, Jake found an old encryption algorithm. The plaintext, key and ciphertext are all four decimal numbers and all greater than 0. The way to get the ciphertext from the plaintext and the key is very simple: the ciphertext is the last four digits of the product of the plaintext and the key (for example: the plaintext is 2010 and the key is 4024, and then the product is 8088240. So the ciphertext is 8240).
Note that the plaintext and the key don’t have leading 0, while the ciphertext might have. Now given the plaintext and the key, you are asked to figure out the ciphertext for Jake quickly.
Input
The first line is an integer T, which presents the number of test cases. Then there are T lines, each line has two integers, the first integer is the plaintext and the second is the key.
Output
For each test case, output the ciphertext.
Sample Input
2
2010 4024
1234 1111
Sample Output
8240
0974
Problem B. Simple Line Editor
Description
puter used line editor, which allowed text to be created and changed only within one line at a time. However, in line editor programs, typing, editing, and document display do not occur simultaneously (unlike the modern text editor like Microsoft Word). Typically, typing does not enter text directly into the document. Instead, users modify the document text by entering mands on a text-only terminal.
Here is an example of a simple line editor which can only process English. In addition, it has mands. ‘@’ and ‘#’. ‘#’ means to cancel the previous letter, and ‘@’ is mand which invalidates all the letters typed before. That is to say, if you want type “aa”, but have mistakenly entered “ab”, then you should enter ‘#a’ or ‘***@aa’ to correct it. Note that if there