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#include "aoc.h"
#include <map>
#include <set>
namespace aoc2022 {
typedef elf (*elf_move)(elf);
typedef bool (*elf_predicate)(elf, const std::set<elf>&);
static elf nomove(elf e) { return e; }
static elf north(elf e) { return elf{e.x, e.y - 1}; }
static elf south(elf e) { return elf{e.x, e.y + 1}; }
static elf west(elf e) { return elf{e.x - 1, e.y}; }
static elf east(elf e) { return elf{e.x + 1, e.y}; }
bool eight(elf e, const std::set<elf>& elves) {
elf es[8] = {
{e.x - 1, e.y - 1}, {e.x, e.y - 1}, {e.x + 1, e.y - 1}, {e.x - 1, e.y},
{e.x + 1, e.y}, {e.x - 1, e.y + 1}, {e.x, e.y + 1}, {e.x + 1, e.y + 1},
};
for (auto& e : es) {
if (elves.find(e) != elves.end()) {
return false;
}
}
return true;
}
bool north_three(elf e, const std::set<elf>& elves) {
elf es[3] = {
{e.x - 1, e.y - 1},
{e.x, e.y - 1},
{e.x + 1, e.y - 1},
};
for (auto& e : es) {
if (elves.find(e) != elves.end()) {
return false;
}
}
return true;
}
bool south_three(elf e, const std::set<elf>& elves) {
elf es[3] = {
{e.x - 1, e.y + 1},
{e.x, e.y + 1},
{e.x + 1, e.y + 1},
};
for (auto& e : es) {
if (elves.find(e) != elves.end()) {
return false;
}
}
return true;
}
bool west_three(elf e, const std::set<elf>& elves) {
elf es[3] = {
{e.x - 1, e.y - 1},
{e.x - 1, e.y},
{e.x - 1, e.y + 1},
};
for (auto& e : es) {
if (elves.find(e) != elves.end()) {
return false;
}
}
return true;
}
bool east_three(elf e, const std::set<elf>& elves) {
elf es[3] = {
{e.x + 1, e.y - 1},
{e.x + 1, e.y},
{e.x + 1, e.y + 1},
};
for (auto& e : es) {
if (elves.find(e) != elves.end()) {
return false;
}
}
return true;
}
static struct elf_test {
elf_predicate p;
elf_move m;
} moves[5] = {{eight, nomove}, {north_three, north}, {south_three, south}, {west_three, west}, {east_three, east}};
bool duplicate(elf e, const std::map<elf, int>& dups) {
auto it = dups.find(e);
return it != dups.end() && it->second > 1;
}
std::vector<elf> round(int i, const std::vector<elf>& elfs, const std::set<elf>& elves, size_t* n) {
std::vector<elf> next;
*n = 0;
for (auto& e : elfs) {
if (moves[0].p(e, elves)) {
next.emplace_back(moves[0].m(e));
*n += 1;
} else {
bool can_move{false};
for (int x = 0; x < 4; x++) {
int index = (i + x) % 4 + 1;
if (moves[index].p(e, elves)) {
next.emplace_back(moves[index].m(e));
can_move = true;
break;
}
}
if (!can_move) {
next.emplace_back(e);
}
}
}
std::map<elf, int> dups;
for (auto& e : next) {
auto kv = dups.insert({e, 1});
if (!kv.second) {
kv.first->second += 1;
}
}
// check duplicate of next
for(size_t i = 0; i < next.size(); i++) {
if (duplicate(next[i], dups)) {
next[i] = elfs[i]; // stay put
}
}
return next;
}
int count(const std::vector<elf>& elfs, const std::set<elf>& elvs) {
int minx{INT32_MAX}, miny{INT32_MAX};
int maxx{INT32_MIN}, maxy{INT32_MIN};
for (auto& e: elfs) {
minx = std::min(e.x, minx);
miny = std::min(e.y, miny);
maxx = std::max(e.x, maxx);
maxy = std::max(e.y, maxy);
}
int n{0};
for (int y = miny; y <= maxy; y++) {
for (int x = minx; x <= maxx; x++) {
if (elvs.find(elf{x, y}) == elvs.end()) n++;
}
}
return n;
}
std::pair<int, int> day23(line_view file) {
int height{0};
std::vector<elf> elfs;
per_line(file, [&height, &elfs](line_view lv) {
for (size_t i = 0; i < lv.length; i++) {
if (*(lv.line + i) == '#') {
elfs.emplace_back(elf{(int)i, height});
}
}
height++;
return true;
});
std::set<elf> elves{elfs.begin(), elfs.end()};
size_t n{0};
int r{0};
while (r < 10 /*true*/) {
elfs = round(r++, elfs, elves, &n);
if (n == elfs.size()) break;
elves.clear();
elves = std::set<elf>{elfs.begin(), elfs.end()};
}
int n1 = count(elfs, elves);
return {n1, r};
}
} // namespace aoc2022
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