rrle.cpp

// Algorism = not 'Algorithm'
/* 
1 < N < 100,000

예)
입력 : abaccchhaa
결과 : b1a1c3h2a3
*/

#include "stdafx.h"
#include <gtest\gtest.h>
#include <vector>

std::string ToString(int value) {
  char buffer[255];
  const errno_t error = ::_ltoa_s(value, buffer, 10);
  if (error != 0) {
    return "";
  }
  return buffer;
}

std::string ToString(const std::vector<std::pair<char, int>>& source) {
  std::string result;
  result.reserve(source.size() * 2);
  for (auto& p : source) {
    result.append(1, p.first);
    result.append(ToString(p.second));
  }
  return result;
}

std::vector<std::pair<char, int>> Solve(const std::string& source) {
  std::vector<std::pair<char, int>> result_vector;
  for (auto it = source.begin(); it != source.end(); ++it) {
    const char ch = *it;
    if (result_vector.empty() || result_vector.rbegin()->first != ch) {
      result_vector.emplace_back(ch, 0);
    }
    result_vector.rbegin()->second += 1;
  }
  if (result_vector.size() > 1) {
    if (result_vector.front().first == result_vector.rbegin()->first) {
      result_vector.rbegin()->second += 1;
    } else {
      result_vector.emplace_back(*result_vector.rbegin());
    }
    result_vector.erase(result_vector.begin());
  }
  return std::move(result_vector);
}

TEST(Test, Test) {
  auto test_string = "abaccchhaa";
  auto result = Solve(test_string);
  EXPECT_STREQ("b1a1c3h2a3", ToString(result).c_str());
}

int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}