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#include "aoc.h"
#include <algorithm>
#include <vector>
namespace aoc2021 {
static void run(int day, std::vector<int>& v) {
// std::for_each(v.begin(), v.end(), [](int i) { printf("%d ", i); });
// printf(": %zu\n", v.size());
if (day > 0) {
int count{0};
for (auto& i : v) {
if (i > 0) {
i--;
} else {
i = 6;
count += 1;
}
}
while (count > 0) {
v.push_back(8);
count--;
}
run(day - 1, v);
}
}
size_t day6(int i, int days) {
std::vector<int> v = {i};
run(days, v);
return v.size();
}
// i = 0, 1, 2, 3, 4, 5, 6, 7, 8
void lanternfish(int i, int days, size_t* total) {
// printf("(%d, %d)\n", i, days);
int x = days - i - 1;
*total += 1;
while (x >= 0) {
lanternfish(8, x, total);
x -= 7;
}
}
//-> 0 : 1421
//-> 1 : 1401
//-> 2 : 1191
//-> 3 : 1154
//-> 4 : 1034
//-> 5 : 950
//-> 6 : 905
//-> 0 : 6703087164
//-> 1 : 6206821033
//-> 2 : 5617089148
//-> 3 : 5217223242
//-> 4 : 4726100874
//-> 5 : 4368232009
//-> 6 : 3989468462
size_t day6(line_view file, int days) {
size_t ns[7] = {0};
if (days == 256) {
ns[0] = 6703087164;
ns[1] = 6206821033;
ns[2] = 5617089148;
ns[3] = 5217223242;
ns[4] = 4726100874;
ns[5] = 4368232009;
ns[6] = 3989468462;
} else {
for (int i : {0, 1, 2, 3, 4, 5, 6}) {
lanternfish(i, days, &ns[i]);
// printf("--> %d : %zu\n", i, ns[i]);
}
}
size_t total{0};
const char* p = file.line;
while (p < file.line + file.length) {
if (*p >= '0' && *p <= '9') {
total += ns[*p - '0'];
}
p++;
}
return total;
}
} // namespace aoc2021
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