Question

This is a question about tries and compression in an algorithms course i'm taking.

Problem 7. Give the LZW encoding the string all consisting of N repeats of the character a. What is the compression ratio as a function of N?

Answer 1

I am attaching the code of the compression :

The output is also given.

Answer 2

I am attaching the code of the compression :

Oct 30 9:35 PM Activities Google Chrome M Inbox (5,203) - rshzb 14.7© x M Activation mail - Login an x f → e onlinegdb.com/online_C++_compiler C HomeworkLib X G give the lzw encoding oft x as LZW (Lempel-ziv-Welch) x Online C++ Compiler-onli x + Run Debug Stop Share Save {} Beautify Language C++ - OnlineGDB beta online compiler and debugger for c/c++ code. compile. run. debug. share. IDE My Projects Classroom new Learn Programming Programming Questions Sign Up Login main.cpp #include <bits/stdC++.h> 2 using namespace std; 3 vector<int> encoding(string s1) 4-{ 5 cout << "Encoding\n"; 6 unordered_map<string, int> table; 7 for (int i = 0; i <= 255; i++) { string ch ch += char(i); 10 table[ch] i; 11 11 } 13 string P 14 P += 51[0]; int code 10 vector<int> output_code; 17 cout << "String toutput_code\tAddition\n"; for (int i = 0; i s1.length(); i++) { if (i != si.length() 1) 20 C += 51[i + 1]; if (table.find(p + c) != table.end()) { P = P + C; } else { cout << p << "\t" << table[p] << "\t\t" << P + c << "\t" << code << endl; output_code.push_back(table[p]); 28 table[P c] = code; code++; P = c; } 256; f + 31.3K < } cout << p < "\t". « table[p] << endl; output_code.push_back(table[p]); return output_code; 37 } 38 39 40 int maio/ input WYS WY 256 WYS 262 S* 258 S*W 263 262 WYSW 264 WYS 262 WYSG 265 G 71 Output Codes are: 87 89 83 42 256 71 256 258 262 262 71 About FAQ Blog Terms of Use . Contact Us. GDB Tutorial Credits . Privacy © 2016 - 2020 GDB Online ... Program finished with exit code o Press ENTER to exit console. I (< + S I

Oct 30 9:35 PM Activities Google Chrome M Inbox (5,203) - rshzb 14.7© x M Activation mail - Login an x f → e onlinegdb.com/online_C++_compiler C HomeworkLib X G give the lzw encoding oft x as LZW (Lempel-ziv-Welch) x Online C++ Compiler-onli x + Run Debug Stop Share Save {} Beautify Language C++ - OnlineGDB beta online compiler and debugger for c/c++ main.cpp code. compile. run. debug. share. 256; IDE My Projects 13 14 15 15 10 17 17 18 19 13 20 20 21 22 23 22 24, Classroom new Learn Programming string P P += 51[0]; int code vector<int> output_code; cout << "String toūtput_code\tAddition\n"; for (int i = 0; i < 51. length(); i++) { if (i != sí.length() C += 51[i 1]; if (table.find(p + c) != table.end()) { P = P + c; } else { cout << p << "\t" table[p] << "\t\t" р C<< "\t" << code << endl; output_code.push_back(table[p]); table(P + c] code; code++; р C; Programming Questions Sign Up Login f + 31.3K ""; } cout << p << "\t" << table[p] << endl; output_code.push_back(table[p]); return output_code; } < int main() 41 - { 42 43 string s = "WYS*WYGWYS*WYSWYSG"; vector<int> output_code encoding(s); 45 cout << "Output Codes are: "; 46 for (int i = 0; i < output_code.size(); i++) { 47 cout << output_code[i] << " "; 48 } 49 cout << endl; 50 51 input WY 256 WYS 262 S* 258 S*W 263 WYS 262 WYSW 264 WYS 262 WYSG 265 G 71 Output Codes are: 87 89 83 42 256 71 256 258 262 262 71 About FAQ Blog Terms of Use . Contact Us. GDB Tutorial Credits . Privacy © 2016 - 2020 GDB Online ... Program finished with exit code o Press ENTER to exit console. (< + S I
The output is also given.