Simplify Path

See the original problem on HackerRank.

Given an absolute path for a file (Unix-style), simplify it.

This challenge simulates an interview problem. As you see, no more information about input constraints are provided. You - probably - have to interact with Marco (who impersonates the interviewer) and ask him some questions to refine your knowledge about the problem.

Input Format

Only a string is provided. The path always begins with ‘/’ (root directory).

Output Format

The path simplified.

Solutions

A Javascript solution by Simone Busoli:

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function processData(input) {
    console.log('/' + input.split('/').reduce(([h, ...t] = [], f) => {
        if (!f || f === '.') return [h, ...t]
        if(f === '..') return [...t]
        return [f, h, ...t]
    }, []).reverse().join('/').replace(/^\/*/, '').replace(/\/*$/, ''))
}

A C++ solution by Alessandro Pezzato using a stack (implemented by std::vector).

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#include <iostream>
#include <vector>

int main() {
  std::vector<std::string> s;

  std::string d;

  while (std::cin) {
    char c = std::cin.get();

    if (c == '/' || c == '\n' || c == EOF) {

      if (d == "..") {
        if (!s.empty()) {
          s.pop_back();
        }
      } else if (d != "." && !d.empty()) {
        s.push_back(std::move(d));
      }

      d.clear();
    } else {
      d.push_back(c);
    }
  }

  if (s.empty()) {
    std::cout << "/";
  } else {
    for (auto t : s) {
      std::cout << "/" << t;
    }
  }
}
stack 
We've worked on this challenge in these gyms: modena  padua  milan 
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