// Determine if a string has all-unique characters.

#define CATCH_CONFIG_MAIN
#include <catch.hpp>

#include <experimental/string_view>
#include <string>
#include <unordered_map>

using string_view = std::experimental::string_view;

auto count(string_view str) {
  std::unordered_map<char, int> c;

  for (auto ch : str) {
    // default value is zero.
    c[ch] += 1;
  }

  return c;
}

bool is_permutation(string_view lhs, string_view rhs) {
  // unordered_map does elementwise comparison.
  return count(lhs) == count(rhs);
}

TEST_CASE("cc12", "is_permutation") {
  REQUIRE(is_permutation("abc", "abc") == true);
  REQUIRE(is_permutation("abc", "cba") == true);
  REQUIRE(is_permutation("abc", "def") == false);
  REQUIRE(is_permutation("aabbbc", "abacbb") == true);
  REQUIRE(is_permutation("aabbbc", "abacb") == false);
}