advent-of-code/2024/11/main-2.cpp
2024-12-10 21:27:18 -08:00

43 lines
638 B
C++

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
ull getn(int i, ull n) {
static map<pair<int, ull>, ull> m;
if (m.contains({i, n})) {
return m[{i, n}];
}
ull ret;
if (i == 0) {
ret = 1;
} else if (n == 0) {
ret = getn(i - 1, 1);
} else {
int nd = log10(n) + 1;
if (nd % 2 == 0) {
ull l = pow(10, nd / 2);
ret = getn(i - 1, n % l) + getn(i - 1, n / l);
} else {
ret = getn(i - 1, n * 2024);
}
}
m[{i, n}] = ret;
return ret;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
ull ret = 0;
while (cin >> n) {
ret += getn(75, n);
}
cout << ret << '\n';
}