#include "dna.h"
#include <cstdio>
#include <algorithm>
using namespace std;
const int MAXN = 112345;
int char_to_int(char c) {
if (c == 'A') return 0;
if (c == 'C') return 1;
return 2;
}
char int_to_char(int x) {
if (x == 0) return 'A';
if (x == 1) return 'C';
return 'T';
}
int occur[2][3][MAXN];
int diff[MAXN];
int tot_pairs[3][3][MAXN];
int n;
void init(string a, string b) {
// printf("%s\n%s\n", a.c_str(), b.c_str());
// printf("init started\n");
n = (int) a.size();
for (int i = 1; i <= n; i++) {
for (int k = 0; k < 3; k++) {
occur[0][k][i] = occur[0][k][i - 1];
occur[1][k][i] = occur[1][k][i - 1];
for (int r = 0; r < 3; r++) {
for (int s = 0; s < 3; s++) {
tot_pairs[r][s][i] = tot_pairs[r][s][i - 1];
}
}
}
int val_a = char_to_int(a[i - 1]);
occur[0][val_a][i]++;
int val_b = char_to_int(b[i - 1]);
occur[1][val_b][i]++;
tot_pairs[val_a][val_b][i]++;
if (val_a != val_b) {
diff[i] = diff[i - 1] + 1;
} else {
diff[i] = diff[i - 1];
}
}
/* printf("init finished\n");
printf("occur:\n");
for (int s = 0; s < 2; s++) {
for (int k = 0; k < 3; k++) {
printf("%d %c: ", s, int_to_char(k));
for (int i = 1; i <= n; i++) {
printf("%d ", occur[s][k][i]);
}
printf("\n");
}
}
printf("diff:\n");
for (int i = 1; i <= n; i++) {
printf("%d ", diff[i]);
}
printf("\n");
printf("tot_pairs:\n");
for (int i = 1; i <= n; i++) {
printf("i = %d\n", i);
printf(" %c %c %c\n", int_to_char(0), int_to_char(1), int_to_char(2));
for (int r = 0; r < 3; r++) {
printf("%c ", int_to_char(r));
for (int s = 0; s < 3; s++) {
printf("%d ", tot_pairs[r][s][i]);
}
printf("\n");
}
printf("\n\n");
} */
}
int get_distance(int x, int y) {
x++; y++;
for (int k = 0; k < 3; k++) {
int count_a = occur[0][k][y] - occur[0][k][x - 1];
int count_b = occur[1][k][y] - occur[1][k][x - 1];
if (count_a != count_b) {
return -1;
}
}
int num_diff = diff[y] - diff[x - 1];
int num_pairs = 0;
for (int r = 0; r < 3; r++) {
for (int s = r + 1; s < 3; s++) {
int r_to_s = tot_pairs[r][s][y] - tot_pairs[r][s][x - 1];
int s_to_r = tot_pairs[s][r][y] - tot_pairs[s][r][x - 1];
num_pairs += min(r_to_s, s_to_r);
}
}
int num_triples = (num_diff - 2 * num_pairs) / 3;
// printf("%d %d %d\n", num_diff, num_pairs, num_triples);
return num_pairs + 2 * num_triples;
}
