Hello! So, I've encountered this problem, on the site I usually work on, that requires me to 'decompress' a 'compressed' string. The code I came up with gives 4 Correct Answers and 6 Wrong Answers. The problem goes like this:

Consider the pattern n[string], which is equivalent to the succession (string) ... (string) ((string) repeated n times). Starting with this model, any string can be compressed.

For example:

- 1[a] is equivalent to a
- 2[ab] is equivalent to abab
- 2[a2[b]] is equivalent to abbabb
- 3[b2[ca]] is equivalent to bcacabcacabcaca

Requirement

Given a compressed string of characters, display its decompression.

Input data

The program reads from the keyboard a correctly compressed stringof characters S.

Output data

The program will display a string of characters that will represent the decompression of the string S.

Restrictions and clarifications

- 3 ≤ the length of the string S ≤ 1000
- decompressed string length ≤ 100,000
- the string S will contain only lowercase letters of the English alphabet
- Time limit: 0.6 seconds
- Memory limit: 64 MB (global) / 8 MB (local)

Example

Input 1

3[a1[b2[c]]]

Output 1

abccabccabcc

Input 2

3[a2[c]]2[x3[y]]

Output 2

accaccaccxyyyxyyy

My code:

Code:#include <iostream> #include <string> #include <cctype> string input; int createNumber(int &pos) { int number = 0; while (isdigit(input[pos])) number = number * 10 + input[pos] - '0', input.erase(input.begin() + pos); return number; } string insideParanthesis(int &pos) { if (input.length()) { input.erase(input.begin() + pos); string toRepeat = ""; while (input[pos] != ']') { while (isalpha(input[pos]) && pos < input.length()) pos++, toRepeat += input[pos - 1]; if (isdigit(input[pos])) { int timesExpr = createNumber(pos); int posStart = pos; timesExpr--; string expr = insideParanthesis(pos); if (timesExpr < 0) { input.erase(input.begin() + posStart, input.begin() + pos); continue; } while (timesExpr--) input.insert(pos, expr), toRepeat += expr, pos += expr.length(); toRepeat += expr; } } input.erase(input.begin() + pos); return toRepeat; } return ""; } int main() { ios_base::sync_with_stdio(false); getline(cin, input); for (int i = 0; i < input.length(); i++) { if (isdigit(input[i])) { int timesExpr = createNumber(i); int iStart = i; timesExpr--; string expr = insideParanthesis(i); if (timesExpr < 0 && input.length()) { input.erase(input.begin() + iStart, input.begin() + i); continue; } else if (!(input.length())) return 0; while (timesExpr--) input.insert(i, expr); } } for (int i = 0; i < input.length(); i++) { if (input[i] == '[' || input[i] == ']') continue; else cout << input[i]; } }

I'd like to add that I've seen sumbitted sources on C++ with the same runtime as my source, but with 10 test cases correct out of 10.

If someone has any advice that could help me get those test cases right, I'd be thankful.