#include "mushrooms.h"
#include <bits/stdc++.h>
using namespace std;
int seed = time(0);
bool swapped = false;
int i = 1;
int just_count_A = 0;
int just_count_B = 0;
vector<int> A = { 0 };
vector<int> B = { };
vector<int> idx;
int calc_pivots_size(int n) {
return 1 + 3*sqrt(n)/4;
}
void make_swap() {
swapped = not swapped;
swap(just_count_A, just_count_B);
swap(A, B);
}
bool decide_swap() {
if (A.size() < B.size()) {
make_swap();
}
return true;
}
int handle_parity(int parity) {
(parity == 0 ? A : B).push_back(idx[i]);
return 1;
}
int handle_pair(int raw_info) {
int even024 = raw_info - (raw_info%2);
if (even024 == 2) {
throw invalid_argument("conflict: need more info to handle this case");
}
(even024 == 0 ? A : B).push_back(idx[i]);
(even024 == 0 ? A : B).push_back(idx[i+1]);
return 2;
}
int handle_conflict_pair(int raw_info) {
int flag3b = raw_info - 1;
(flag3b & 0b100 ? A : B).push_back(idx[i]);
(flag3b & 0b100 ? B : A).push_back(idx[i+1]);
(flag3b & 0b010 ? B : A).push_back(idx[i+2]);
(flag3b & 0b001 ? B : A).push_back(idx[i+3]);
return 4;
}
void get_pivots(int n) {
int info;
int size = calc_pivots_size(n);
while (decide_swap() and (int)A.size() < size and i+5 < n) {
if (A.size() < 2) {
i += handle_parity(use_machine({ idx[i], A[0] }));
} else if (A.size() < 3 or B.size() < 2) {
info = use_machine({ idx[i], A[0], idx[i+1], A[1] });
i += handle_parity(info%2);
i += handle_parity(info/2);
} else {
info = use_machine({ idx[i], A[0], idx[i+1], A[1], idx[i+2], A[2] });
i += handle_parity(info%2);
try {
i += handle_pair(info);
} catch (const invalid_argument &) {
info = use_machine({ B[0], idx[i], B[1], A[0], idx[i+1], A[1], idx[i+2], A[2], idx[i+3] });
i += handle_conflict_pair(info);
}
}
}
}
vector<int> make_sample(int size) {
vector<int> sample = { };
for (int j=0; j<size; j++) {
sample.insert(sample.end(), { idx[i+j], A[j] });
}
return sample;
}
void count_the_rest(int n) {
while (decide_swap() and i < n) {
int test_size = min((int)A.size(), n-i);
int info = use_machine(make_sample(test_size));
i += handle_parity(info%2);
i += test_size-1;
just_count_A += (test_size-1) - (info/2);
just_count_B += info/2;
}
}
int count_mushrooms(int n) {
srand(seed);
idx.push_back(0);
for(int i=1;i<n;i++) idx.push_back(i);
random_shuffle(idx.begin()+1, idx.end());
get_pivots(n);
count_the_rest(n);
if (swapped) {
make_swap();
}
return A.size() + just_count_A;
}
