mirror of
https://github.com/xlucn/PAT.git
synced 2026-10-08 16:52:43 +08:00
38 lines
1.5 KiB
HTML
38 lines
1.5 KiB
HTML
<!DOCTYPE html>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
|
<h1>1069. The Black Hole of Numbers (20)</h1>
|
|
<div id="problemContent">
|
|
<p>For any 4-digit integer except the ones with all the digits being the same, if we sort the digits in non-increasing order first, and then in non-decreasing order, a new number can be obtained by taking the second number from the first one. Repeat in this manner we will soon end up at the number 6174 -- the "black hole" of 4-digit numbers. This number is named Kaprekar Constant.</p>
|
|
<p>For example, start from 6767, we'll get:</p>
|
|
<p>
|
|
7766 - 6677 = 1089<br/>
|
|
9810 - 0189 = 9621<br/>
|
|
9621 - 1269 = 8352<br/>
|
|
8532 - 2358 = 6174<br/>
|
|
7641 - 1467 = 6174<br/>
|
|
... ...</p>
|
|
<p>Given any 4-digit number, you are supposed to illustrate the way it gets into the black hole.</p>
|
|
<p><b>
|
|
Input Specification:
|
|
</b></p>
|
|
<p>Each input file contains one test case which gives a positive integer N in the range (0, 10000).</p>
|
|
<p><b>
|
|
Output Specification:
|
|
</b></p>
|
|
<p>If all the 4 digits of N are the same, print in one line the equation "N - N = 0000". Else print each step of calculation in a line until 6174 comes out as the difference. All the numbers must be printed as 4-digit numbers.</p>
|
|
<b>Sample Input 1:</b><pre>
|
|
6767
|
|
</pre>
|
|
<b>Sample Output 1:</b><pre>
|
|
7766 - 6677 = 1089
|
|
9810 - 0189 = 9621
|
|
9621 - 1269 = 8352
|
|
8532 - 2358 = 6174
|
|
</pre>
|
|
<b>Sample Input 2:</b><pre>
|
|
2222
|
|
</pre>
|
|
<b>Sample Output 2:</b><pre>
|
|
2222 - 2222 = 0000
|
|
</pre>
|
|
</div> |