/** * Author : ~swim~ * Date : 28-Jun-2018 * Description : [Challenge] Crypto_Cube : Imagine a cube, which can contain characters at its vertices. Each vertex can contain a single character. For example, we can store the string "SoloLearn" in a cube. 'S' will be stored at the position (0, 0, 0) , 'o' at (0, 1, 0) , 'l' at (1, 1, 0) , 'o' at (1, 0, 0), 'L' at (0, 0, 1), 'e' at (0, 1, 1), 'a' at (1, 1, 1), 'r' at (1, 0, 1). As each cube has only 8 vertices, we will need another cube to store the last character. A string of 100 characters will require 100/8: 13 cubes to store all the characters. Reading from and writing to a cube is done in the sequence: (0, 0, 0), (0, 1, 0), (1, 1, 0), (1, 0, 0), (0, 0, 1), (0, 1, 1), (1, 1, 1), (1, 0, 1). Each cube can be rotated left, right, up and down. After each rotation, the characters move from their vertices to corresponding neighbor vertices. Let's consider the example from above: the first cube contains "SoloLear" and the second cube contains the leftover "n". If we rotate the first cube to the right once we will get: Reading the rotated cube will result in "LeoSralo". We can rotate as many times as we want, for instance, let's rotate up: Now reading the cube will result in "rLSoaeol". TASK: Write a program that encrypts a given string by randomly rotating the corresponding cubes, as well as decrypts the string, given the encrypted string and the rotation sequence. For instance, for the text "I love coding and SoloLearn" you will need 4 cubes and here's a random sample of rotations: 0:U:U:L:R,1:U,2:D:R,3:U:R 0, 1, 2 or 3 are the numbers of the cubes, U, L R D are the rotation directions (Up, Left, Right, Down). Cube rotations are comma-separated. Each cube can have multiple rotations, separated by colons. So, 0:U:U:L:R means that the first cube is rotated up, then again up, to the left, and finally to the right. Input : 1. Line 1 - Enter the string to be encrypted 2. Line 2 - Encryption sequence in the format specified in the description You can directly press submit, in that case test data will be used Output : First the encrypted string showing the intermediate steps. Followed by Decrypted string showing the intermediate steps Note: If you get time_limit_exceeded error try entering a shorter input string and/or shorter encrypting sequence. Note: Comprehensive input testing is not done as it was getting quite tedious :) Enjoy the program and Thank you for patience :) */ #include #include #include #include #include #include #include using namespace std; namespace { char const DELM1 = ','; char const DELM2 = ':'; char const NL = '\n'; int const BSZ = 8; // rotation directions string const U {"U"}; string const D {"D"}; string const R {"R"}; string const L {"L"}; using Cube = string; using CBox = vector; using Idx = vector; // pair.first is used for encryption and pair.second // is used for decryption using Idxpair = pair; using RMAP = map>; // association of cube number and enc_dec keys using C_Encdec_key_b = pair>; // complete sequence of enc_dec keys for each block of the input string using Encdec_Seq = vector; // error tag classes for use in exception struct Invalid_Cube_Number : exception {}; struct Invalid_Enc_dec_key : exception {}; struct Bad_format : exception {}; // Helper method, bool rev=false is for // encryption and use pair.first and bool // rev=true is for decryption, use // pair.second auto Rotate = [](auto const& cube, Idxpair const& idx, bool rev) { Cube cb(BSZ, ' '); int i=0; for(auto& e : cb) { e = cube.at(!rev ? idx.first[i]:idx.second[i]); cout << cb.substr(0,i+1) << string(BSZ-i-1, '#') << NL; i++; } cout << NL; return cb; }; // map of string to rotation function. The // string determines which function to call RMAP rMap { // RotateUp, bool rev = false is for // encryption. bool rev = true is for // decryption {U, [](Cube& cube, bool rev = false) { static Idxpair const idx{ {4, 0, 3, 7, 5, 1, 2, 6}, {1, 5, 6, 2, 0, 4, 7, 3} }; cube = Rotate(cube, idx, rev);} }, // RotateDown, bool rev = false is for // encryption, bool rev = true is for // decryption {D, [](Cube& cube, bool rev = false) { static Idxpair const idx{ {1, 5, 6, 2, 0, 4, 7, 3}, {4, 0, 3, 7, 5, 1, 2, 6} }; cube = Rotate(cube, idx, rev);} }, // RotateRight,bool rev = false is for // encryption, bool rev = true is for // decryption {R, [](Cube& cube, bool rev = false) { static Idxpair const idx{ {4, 5, 1, 0, 7, 6, 2, 3}, {3, 2, 6, 7, 0, 1, 5, 4} }; cube = Rotate(cube, idx, rev);} }, // RotateRight, bool rev = false is for // encryption, bool rev = true is for // decryption {L, [](Cube& cube, bool rev = false) { static Idxpair const idx{ {3, 2, 6, 7, 0, 1, 5, 4}, {4, 5, 1, 0, 7, 6, 2, 3}}; cube = Rotate(cube, idx, rev);} }}; // end RMap // Parse, validate and store the enc_dec key seq auto Parse_Encdec_key_seq=[](string inp, int nBox) { stringstream ssdelm1(inp); string delm1split; Encdec_Seq encdec_s; // split on delimiter 1(',' here) while(getline(ssdelm1, delm1split, DELM1)) { int cubeno; try { cubeno = stoi(delm1split); } catch(...) { throw Bad_format(); } if(cubeno > nBox) throw Invalid_Cube_Number(); stringstream ssdelm2(delm1split); string delm2split; // split on delimiter 2 (':' here) // remove the cube no from the // string getline(ssdelm2, delm2split, DELM2); vector keys; while(getline(ssdelm2, delm2split, DELM2)) { // check for valid enc_dec key if(delm2split != U && delm2split != D && delm2split != R && delm2split != L) throw Invalid_Enc_dec_key(); keys.emplace_back(delm2split); } // add to the final sequence encdec_s.emplace_back(cubeno, keys); } // end while(getline(...)) return encdec_s; }; // Split the input string to multiple boxes. Each box contains 8 characters. The last box may contain some empty characters auto Split_to_boxes = [](auto const& inp) { int nbox = inp.size()/BSZ; nbox += (inp.size()%BSZ ? 1 : 0); CBox cbx; for(auto i=0; iint { // user input string inp; getline(cin, inp); string enc_dec_seq; getline(cin, enc_dec_seq); if(inp.empty() && enc_dec_seq.empty()) { cout << "No user input supplied," " using test data : \n"; inp = "I_love_coding_and_SoloLearn"; enc_dec_seq = "0:R:U:D,1:L:R:U,0:D:R:D,2:D:R,3:L:R"; } // parse and split the input to list // of boxes/cubes of length 8 chars CBox cbx = Split_to_boxes(inp); try { // parse and split the encrypting // sequence auto encdec_s = Parse_Encdec_key_seq (enc_dec_seq, cbx.size()-1); cout << "Input :\n" << inp << NL; cout << "Input as blocks :\n"; DisplayCubes(cbx); // Encrypt the input now Encrypt(cbx, encdec_s); cout << "Final encrypted string :\n"; DisplayCubes(cbx, true); cout << NL << NL; // Decrypt the encrypted input now Decrypt(cbx, encdec_s); cout << "Final decrypted string :\n"; DisplayCubes(cbx, true); cout << NL << NL; } // end try catch(Invalid_Cube_Number&) { cerr << "Invalid cube number" " specified, aborting!\n"; return 0; } catch(Invalid_Enc_dec_key&) { cerr << "Invalid encrypting_" "decrypting key specified," " aborting!\n"; return 0; } catch(Bad_format&) { cerr << "Encryption_decryption" "key sequence has bad format," " aborting!"; return 0; } }

[Challenge] Crypto_Cube.cpp