CPMagical CP Library

Problem solution · Turing

CCC 2009 J3 - Good Times

CCC 2009 J3 - Good Times: a Turing solution using direct simulation. Learn the idea, check the complexity, and read the full code, with credit to CCCSolutions.

Technique
Direct simulation
Source
CCCSolutions
Length
38 lines
Start with the idea.

Try the problem first. If you get stuck, read the approach below, then write your own solution. The full code is at the bottom.

Approach

Direct simulation

For CCC 2009 J3 - Good Times, the implementation follows the problem’s operations directly while maintaining only the state needed for the next decision.

  1. Translate each rule into one explicit state update.
  2. Maintain the invariant after every processed item.
  3. Return the accumulated state once all relevant input has been handled.

Code notes

  • 38 lines of Turing from the credited upstream file ccc09j3.t.
  • The implementation keeps its working state in language-native values and containers.
  • No explicit loop blocks detected.

Complexity

Count the number and nesting of passes over the input, then include the maintained containers in the memory estimate.

Check the problem constraints before deciding whether this complexity will pass.

Source

Code and credit

This code comes from CCCSolutions by CCCSolutions contributors · Milliken Mills High School and is used under the MIT licence.

Open problem ↗Original source ↗
Full codeCCC 2009 J3 - Good Times · TuringTuring
Use this to learn the idea, then write your own version.
% CCC 2009% J3: Good Times%% use a function to adjust time on 24hr clock% function localTime (t : int, c : int) : int    var lt : int    lt := t + c        % adjust for the day before or next day    if lt > 2400 then        lt := lt - 2400    elsif lt < 0 then        lt := lt + 2400    end if        % adjust for the hour rollover    if lt mod 100 >= 60 then        lt := (lt div 100 * 100 + 100) + (lt mod 100 - 60)    end if        result ltend localTime var OttawaTime : int get OttawaTimeput localTime (OttawaTime, 0), " in Ottawa"put localTime (OttawaTime, - 300), " in Victoria"put localTime (OttawaTime, - 200), " in Edmonton"put localTime (OttawaTime, - 100), " in Winnipeg"put localTime (OttawaTime, 0), " in Toronto"put localTime (OttawaTime, 100), " in Halifax"put localTime (OttawaTime, 130), " in St. John's"

Keep practising

Did this explanation save you time? I'm a Grade 11 student building this free library to make difficult algorithms easier to understand.

Buy me a coffee ↗