// WIP: REFACTORING
#include "mushrooms.h"
#include <bits/stdc++.h>
using namespace std;
const int M = 100; // TODO magic number! can we determine them in term of n?
bool swapped = false;
int i = 1;
int just_count_A = 0;
int just_count_B = 0;
vector<int> A = { 0 };
vector<int> B = { };
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(i);
return 1;
}
int handle_pair(int result) {
int even = result - (result%2);
if (even == 2) {
throw 4;
}
(even == 0 ? A : B).push_back(i);
(even == 0 ? A : B).push_back(i+1);
return 2;
}
int handle_conflict_pair(int result) {
int flag = result - 1;
(flag & 0b100 ? A : B).push_back(i);
(flag & 0b100 ? B : A).push_back(i+1);
(flag & 0b010 ? B : A).push_back(i+2);
(flag & 0b001 ? B : A).push_back(i+3);
return 4;
}
void get_same_two_pivots() {
while (A.size() < 2 and B.size() < 2) {
i += handle_parity(use_machine({ A[0], i }));
}
}
void get_same_many_pivots() {
int result;
while (decide_swap() and A.size() < M) {
if (A.size() < 3 or B.size() < 2) {
result = use_machine({ i, A[0], i+1, A[1] });
i += handle_parity(result%2);
i += handle_parity(result/2);
} else {
result = use_machine({ i, A[0], i+1, A[1], i+2, A[2] });
i += handle_parity(result%2);
try {
i += handle_pair(result);
} catch (int e) {
result = use_machine({ B[0], i, B[1], A[0], i+1, A[1], i+2, A[2], i+3 });
i += handle_conflict_pair(result);
}
}
}
}
vector<int> make_sample(int size) {
vector<int> sample = { };
for (int j=0; j<size; j++) {
sample.insert(sample.end(), { 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 result = use_machine(make_sample(test_size));
i += handle_parity(result%2);
i += test_size-1;
just_count_A += (test_size-1) - (result/2);
just_count_B += result/2;
}
}
void count_naive(int n) {
while (i < n) {
i += handle_parity(use_machine({ A[0], i }));
}
}
/*
void init_variables() { // program run only once? move this to header?
swapped = false;
i = 1;
just_count_A = just_count_B = 0;
A = { 0 };
B = { };
}
*/
int count_mushrooms(int n) {
//init_variables();
if (n <= 226) {
count_naive(n);
} else {
get_same_two_pivots();
get_same_many_pivots();
count_the_rest(n);
}
if (swapped) {
make_swap();
}
return A.size() + just_count_A;
}
