day11b-hash.cpp (1288B)
1 #include <algorithm> 2 #include <cstdint> 3 #include <iostream> 4 #include <unordered_map> 5 #include <ranges> 6 #include <set> 7 #include <sstream> 8 #include <string> 9 #include <string_view> 10 #include <vector> 11 using namespace std; 12 13 struct hash_pair { 14 template <class T1, class T2> 15 size_t operator()(const std::pair<T1, T2>& p) const { 16 return std::hash<T1>{}(p.first) ^ std::hash<T2>{}(p.second); 17 } 18 }; 19 20 unordered_map<pair<uint64_t, uint64_t>, uint64_t, hash_pair> t; 21 22 pair<uint64_t, uint64_t> split(uint64_t a) { 23 int digits = 0; 24 for (uint64_t b = a; b != 0; b /= 10) 25 digits++; 26 27 if (digits % 2 == 1) 28 return make_pair(0, 0); 29 30 uint64_t j = 1; 31 for (int k = 0; k < digits/2; k++) 32 j *= 10; 33 34 return make_pair(a/j, a%j); 35 } 36 37 uint64_t count(uint64_t a, int n) { 38 if (n == 0) 39 return 1; 40 41 if (auto it = t.find(make_pair(a, n)); it != t.end()) 42 return it->second; 43 44 if (a == 0) 45 return t[make_pair(a, n)] = count(1, n-1); 46 47 if (auto [x, y] = split(a); x != 0) { 48 auto c1 = count(x, n-1); 49 auto c2 = count(y, n-1); 50 return t[make_pair(a, n)] = c1+c2; 51 } 52 53 return t[make_pair(a, n)] = count(a*2024, n-1); 54 } 55 56 int main() { 57 uint64_t x; 58 vector<uint64_t> old, v; 59 while (cin >> x) 60 v.push_back(x); 61 62 uint64_t tot = 0; 63 for (auto a : v) 64 tot += count(a, 75); 65 66 cout << tot << endl; 67 68 return 0; 69 }