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#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cmath>
const bool debug = false;
class Snail {
public:
Snail() {}
Snail(std::string raw) { parse(raw); }
Snail(const Snail *s) : left(s->left), right(s->right) {
if (s->left == -1) left_child = new Snail(s->left_child);
if (s->right == -1) right_child = new Snail(s->right_child);
}
Snail *left_child, *right_child;
int left = -1, right = -1;
void parse(std::string raw) {
int indent = 0;
int comma = 0;
for (int i=0; i<raw.size(); i++) {
if (raw[i] == '[') indent++;
if (raw[i] == ']') indent--;
if (raw[i] == ',' && indent == 1) comma = i;
}
auto l = raw.substr(1, comma);
auto r = raw.substr(comma+1, raw.size()-comma-2);
if (l[0] == '[') left_child = new Snail(l);
else left = std::stoi(l);
if (r[0] == '[') right_child = new Snail(r);
else right = std::stoi(r);
}
std::string show () {
std::string rep = "[";
if (left != -1) rep += std::to_string(left);
else rep += left_child->show();
rep += ",";
if (right != -1) rep += std::to_string(right);
else rep += right_child->show();
return rep + "]";
}
Snail& operator+=(Snail& rhs) {
Snail *temp = new Snail(this);
left_child = temp;
left = -1;
right_child = new Snail(&rhs);
right = -1;
reduce();
return *this;
}
friend Snail operator+(Snail lhs, Snail& rhs) {
lhs += rhs;
return lhs;
}
void reduce () {
while (true) {
if (debug) std::cout << show() << std::endl;
bool dirty = false;
explode(0, &dirty);
if (dirty) continue;
split(&dirty);
if (dirty) continue;
break;
}
}
void spill_up (int spill) {
if (spill > 0) {
if (left == -1) left_child->spill_up(spill);
else left += spill;
}
if (spill < 0) {
if (right == -1) right_child->spill_up(spill);
else right += -spill;
}
}
int explode (int indent, bool *dirty) {
int spill = 0;
if (indent >= 3) {
if (left == -1 && !*dirty) {
if (debug) std::cout << "boom " << show() << " -> ";
left = 0;
if (right == -1) right_child->left += left_child->right;
else right += left_child->right;
int spill = -left_child->left;
*dirty = true;
if (debug) std::cout << show() << " spilled " << spill << std::endl;
return spill;
}
if (right == -1 && !*dirty) {
if (debug) std::cout << "boom " << show() << " -> ";
right = 0;
if (left == -1) left_child->right += right_child->left;
else left += right_child->left;
int spill = right_child->right;
*dirty = true;
if (debug) std::cout << show() << " spilled " << spill << std::endl;
return spill;
}
} else {
if (left == -1) {
spill = left_child->explode(indent+1, dirty);
if (spill > 0) {
if (debug) std::cout << "catch " << spill << " " << show() << " -> ";
if (right != -1) right += spill;
else right_child->spill_up(spill);
spill = 0;
if (debug) std::cout << show() << std::endl;
}
if (spill < 0) return spill;
}
if (right == -1) {
spill = right_child->explode(indent+1, dirty);
if (spill < 0) {
if (debug) std::cout << "catch " << spill << " " << show() << " -> ";
if (left != -1) left += -spill;
else left_child->spill_up(spill);
spill = 0;
if (debug) std::cout << show() << std::endl;
}
if (spill > 0) return spill;
}
}
return spill;
}
void split(bool *dirty) {
if (*dirty) return;
if (left == -1) { left_child->split(dirty); }
else if (left >= 10) {
if (debug) std::cout << "split " << show() << " -> ";
left_child = new Snail();
left_child->left = std::floor(left/2.0);
left_child->right = std::ceil(left/2.0);
left = -1;
*dirty = true;
if (debug) std::cout << show() << std::endl;
return;
}
if (*dirty) return;
if (right == -1) { right_child->split(dirty); }
else if (right >= 10) {
if (debug) std::cout << "split " << show() << " -> ";
right_child = new Snail();
right_child->left = std::floor(right/2.0);
right_child->right = std::ceil(right/2.0);
right = -1;
*dirty = true;
if (debug) std::cout << show() << std::endl;
return;
}
}
int magnitude () {
int mag = 0;
if (left == -1) mag += 3 * left_child->magnitude();
else mag += 3 * left;
if (right == -1) mag += 2 * right_child->magnitude();
else mag += 2 * right;
return mag;
}
};
std::vector<Snail> parse (std::string raw) {
std::vector<Snail> numbers;
while (raw.size() > 0) {
auto newline = raw.find("\n");
if (newline != std::string::npos) {
numbers.emplace_back(raw.substr(0, newline));
raw = raw.substr(newline+1);
} else {
numbers.emplace_back(raw);
}
}
return numbers;
}
int get_largest_perm (std::vector<Snail> nums) {
int max = 0;
for (int i=0; i<nums.size(); i++) {
for (int j=0; j<nums.size(); j++) {
if (j==i) continue;
Snail *a = new Snail(nums[i]);
Snail *b = new Snail(nums[j]);
int mag = (*a + *b).magnitude();
if (debug) std::cout << i << " " << j << " " << mag << std::endl;
max = std::max(max, mag);
}
}
return max;
}
int main (int argc, char *argv[]) {
std::string raw;
std::getline(std::ifstream(argv[1]), raw, '\0');
std::vector<Snail> numbers = parse(raw);
std::cout << "largest sum: " << get_largest_perm (numbers) << std::endl;
int limit = 100000;
if (argc > 2) limit = atoi(argv[2]);
Snail sum { numbers[0] };
for (int i=1; i<numbers.size() && i<limit; i++) {
sum += numbers[i];
if (debug)
std::cout << "sum: " << sum.show()
<< ", mag: " << sum.magnitude() << std::endl;
}
std::cout << "sum: " << sum.show()
<< ", mag: " << sum.magnitude() << std::endl;
return 0;
}
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