#include "dna.h"
#include <algorithm>
#include <map>
#include <numeric>
#include <set>
#include <vector>
std::map<std::string, std::vector<int>> psums;
const std::vector<std::string> poss = {"AT", "AC", "TC", "TA", "CA", "CT"};
const std::vector<std::pair<std::string, std::string>> complements = {
{"AT", "TA"}, {"AC", "CA"}, {"TC", "CT"}};
const std::vector<char> letters = {'A', 'T', 'C'};
int n;
std::map<char, std::vector<int>> A_psum, B_psum;
std::vector<std::string> to_permute;
void init(std::string a, std::string b) {
n = a.length();
for (auto &p : poss) {
psums[p].resize(n + 1);
}
for (auto &c : letters) {
A_psum[c].resize(n + 1);
B_psum[c].resize(n + 1);
psums[std::string(2, c)].resize(n + 1);
}
a = " " + a;
b = " " + b;
for (int i = 1; i <= n; ++i) {
psums[std::string(1, a[i]) + std::string(1, b[i])][i]++;
A_psum[a[i]][i]++;
B_psum[b[i]][i]++;
}
for (auto &p : psums) {
std::vector<int> res(p.second.size());
std::partial_sum(p.second.begin(), p.second.end(), res.begin());
p.second = res;
}
for (auto &p : A_psum) {
std::vector<int> res(p.second.size());
std::partial_sum(p.second.begin(), p.second.end(), res.begin());
p.second = res;
}
for (auto &p : B_psum) {
std::vector<int> res(p.second.size());
std::partial_sum(p.second.begin(), p.second.end(), res.begin());
p.second = res;
}
std::set<std::string> st;
for (int i = 0; i < 6; ++i) {
for (int j = 0; j < 6; ++j) {
for (int k = 0; k < 6; ++k) {
if (i == j or j == k or i == k) {
continue;
}
if (poss[i][1] == poss[j][0] and poss[j][1] == poss[k][0] and
poss[k][1] == poss[i][0]) {
st.insert(poss[i] + poss[j] + poss[k]);
}
}
}
}
for (auto &s : st) {
to_permute.push_back(s);
}
}
int get_distance(int x, int y) {
++x, ++y;
for (auto &ch : letters) {
if (A_psum[ch][y] - A_psum[ch][x - 1] !=
B_psum[ch][y] - B_psum[ch][x - 1]) {
return -1;
}
}
std::map<std::string, int> sums;
for (auto &p : poss) {
sums[p] = psums[p][y] - psums[p][x - 1];
}
int ans = 0;
for (auto &[u, v] : complements) {
int cur = std::min(sums[u], sums[v]);
ans += cur;
sums[u] -= cur, sums[v] -= cur;
}
std::sort(to_permute.begin(), to_permute.end());
int final_ans = 1e9;
do {
auto mp = sums;
auto cur_ans = ans;
for (auto &s : to_permute) {
auto a = s.substr(0, 2);
auto b = s.substr(2, 2);
auto c = s.substr(4, 2);
int cur = std::min({mp[a], mp[b], mp[c]});
cur_ans += 2 * cur;
mp[a] -= cur, mp[b] -= cur, mp[c] -= cur;
}
final_ans = std::min(final_ans, cur_ans);
} while (std::next_permutation(to_permute.begin(), to_permute.end()));
return final_ans;
}
