tests/hash/md5/yukicoder-8005.test.cpp

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• Last update: 2025-08-17 00:21:01+09:00
• Problem: https://yukicoder.me/problems/no/8005

Depends on

• MD5 Hash (library/hash/md5.hpp)

Code

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

#include "../../../library/hash/md5.hpp"
#define PROBLEM "https://yukicoder.me/problems/no/8005"

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  string s;
  cin >> s;
  cout << asalib::hash::md5(asalib::hash::md5(s)) << '\n';
  return 0;
}

#line 1 "tests/hash/md5/yukicoder-8005.test.cpp"
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

#line 2 "library/hash/md5.hpp"

#line 4 "library/hash/md5.hpp"
#include <bit>
#line 9 "library/hash/md5.hpp"
using namespace std;

namespace asalib::hash {
  constexpr string md5(const string& str) {
    static_assert(endian::native == endian::little, "only little endian");

    vector<uint8_t> bytes;
    for (const char c : str) bytes.emplace_back(c);
    // s: ラウンドごとのシフト数
    array<uint32_t, 64> s;
    {
      constexpr array<uint32_t, 4> r1 = { 7, 12, 17, 22 };
      constexpr array<uint32_t, 4> r2 = { 5, 9, 14, 20 };
      constexpr array<uint32_t, 4> r3 = { 4, 11, 16, 23 };
      constexpr array<uint32_t, 4> r4 = { 6, 10, 15, 21 };
      for (int i = 0; i < 16; ++i) s[i] = r1[i % 4];
      for (int i = 16; i < 32; ++i) s[i] = r2[i % 4];
      for (int i = 32; i < 48; ++i) s[i] = r3[i % 4];
      for (int i = 48; i < 64; ++i) s[i] = r4[i % 4];
    }
    // k: sin(i) * 2^32
    // wikipedia に載ってる前計算の値を使う
    // clang-format off
    constexpr array<uint32_t, 64> k = { 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 };
    // clang-format on
    // 初期値
    uint32_t a0 = 0x67452301, b0 = 0xefcdab89, c0 = 0x98badcfe, d0 = 0x10325476;
    // padding
    bytes.emplace_back(0x80);
    while (bytes.size() % 64 != 56) bytes.emplace_back(0x00);
    uint64_t bitlen = str.size() * 8;
    // little endian で追加
    for (int i = 0; i < 8; ++i) {
      bytes.emplace_back(bitlen & 0xff);
      bitlen >>= 8;
    }
    // process
    assert(bytes.size() % 64 == 0);
    for (int chunk = 0; chunk < static_cast<int>(bytes.size()); chunk += 64) {
      // 512bit のブロックを 32bit ずつに分割
      array<uint32_t, 16> m;
      for (int i = 0; i < 16; ++i) {
        m[i] = 0;
        for (int j = 0; j < 4; ++j) m[i] |= bytes[chunk + i * 4 + j] << (j * 8);
      }
      uint32_t a = a0, b = b0, c = c0, d = d0;
      for (int i = 0; i < 64; ++i) {
        uint32_t f, g;
        if (i < 16) {
          f = (b & c) | ((~b) & d);
          g = i;
        }
        else if (i < 32) {
          f = (d & b) | ((~d) & c);
          g = (5 * i + 1) % 16;
        }
        else if (i < 48) {
          f = b ^ c ^ d;
          g = (3 * i + 5) % 16;
        }
        else {
          f = c ^ (b | (~d));
          g = (7 * i) % 16;
        }
        f += a + k[i] + m[g];
        a = d, d = c, c = b;
        // left rotate x by s[i] bits
        b += rotl(f, s[i]);
      }
      a0 += a, b0 += b, c0 += c, d0 += d;
    }
    vector<uint8_t> digest;
    for (uint32_t x : { a0, b0, c0, d0 }) {
      for (int i = 0; i < 4; ++i) {
        digest.emplace_back(x & 0xff);
        x >>= 8;
      }
    }
    // hex 表記にする
    const string hex = "0123456789abcdef";
    string res = "";
    for (const uint8_t x : digest) {
      res += hex[x >> 4];
      res += hex[x & 0xf];
    }
    return res;
  }

  static_assert(md5("The quick brown fox jumps over the lazy dog") == "9e107d9d372bb6826bd81d3542a419d6");
  static_assert(md5("The quick brown fox jumps over the lazy dog.") == "e4d909c290d0fb1ca068ffaddf22cbd0");
  static_assert(md5("") == "d41d8cd98f00b204e9800998ecf8427e");
}  // namespace asalib::hash
#line 8 "tests/hash/md5/yukicoder-8005.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/8005"

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  string s;
  cin >> s;
  cout << asalib::hash::md5(asalib::hash::md5(s)) << '\n';
  return 0;
}

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