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Problem solution · Turing

CCC 2005 J1 - Cell Sell

CCC 2005 J1 - Cell Sell: 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 2005 J1 - Cell Sell, 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 ccc05j1.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 2005 J1 - Cell Sell · TuringTuring
Use this to learn the idea, then write your own version.
% CCC 2005 Junior problem 1% The Cell Sell%% comparing two cellphone plans, with various rates depending on time% straight forward arithmetic and decision structures var day, night, weekend : intvar planA, planB : realput "Number of daytime minutes?"get dayput "Number of evening minutes?"get nightput "Number of weekend minutes?"get weekendif day > 100 then    planA := (day - 100) * .25 + night * .15 + .20 * weekendelse    planA := night * .15 + .20 * weekendend ifif day > 250 then    planB := (day - 250) * .45 + night * .35 + .25 * weekendelse    planB := night * .35 + .25 * weekendend ifput "Plan A costs ", planA : 0 : 2put "Plan B costs ", planB : 0 : 2 % abs needed because turing stores reals with a potential small errorif abs (planA - planB) < 0.00005 then    put "Plan A and B are the same price."elsif planA > planB then    put "Plan B is the cheapest."else    put "Plan A is the cheapest."end if

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