// Determine if a string is one edit away from another.

#define CATCH_CONFIG_MAIN
#include <catch.hpp>

#include <fmt/format.h>
#include <experimental/string_view>
#include <string>

using string_view = std::experimental::string_view;

std::string compress(string_view in) {
  char last = '\0';
  int count = 0;

  std::stringstream out;

  for (auto ch : in) {
    if (ch != last) {
      if (count != 0) {
        out << last << count;
      }
      last = ch;
      count = 0;
    }
    count++;
  }

  if (count != 0) {
    out << last << count;
  }

  auto compressed = out.str();

  return (compressed.length() < in.length()) ? compressed : std::string(in);
}

TEST_CASE("cc16", "compress") {
  CHECK(compress("aabcccccaaa") == "a2b1c5a3");
  CHECK(compress("aabcccccaaaaaaaab") == "a2b1c5a8b1");
  CHECK(compress("abcdef") == "abcdef");
}