Submission #829971

#	Time	Username	Problem	Language	Result	Execution time	Memory
829971		alex_2008	Mutating DNA (IOI21_dna)	C++17	100 / 100	37 ms	6752 KiB

dna

#include "dna.h"
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
typedef long long ll;
using namespace std;
const int N = 1e5 + 10;
int cnt[N][3][3];
int f(char x) {
	if (x == 'A') return 0;
	if (x == 'C') return 1;
	return 2;
}
void init(string a, string b) {
	int n = (int)a.size();
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j <= 2; j++) {
			for (int k = 0; k <= 2; k++) {
				cnt[i][j][k] = cnt[i - 1][j][k];
			}
		}
		cnt[i][f(a[i - 1])][f(b[i - 1])]++;
	}
}
int get_distance(int x, int y) {
	++x; ++y;
	int cntab = cnt[y][0][1] - cnt[x - 1][0][1], cntac = cnt[y][0][2] - cnt[x - 1][0][2],
	cntba = cnt[y][1][0] - cnt[x - 1][1][0], cntbc = cnt[y][1][2] - cnt[x - 1][1][2], 
	cntca = cnt[y][2][0] - cnt[x - 1][2][0], cntcb = cnt[y][2][1] - cnt[x - 1][2][1];
	if (cntab + cntac != cntba + cntca) return -1;
	if (cntba + cntbc != cntab + cntcb) return -1;
	if (cntca + cntcb != cntac + cntbc) return -1;
	int ans = 0;
	int u = min(cntab, cntba);
	cntab -= u; cntba -= u;
	ans += u;
	u = min(cntac, cntca);
	cntac -= u; cntca -= u;
	ans += u;
	u = min(cntbc, cntcb);
	cntbc -= u; cntcb -= u;
	ans += u;
	int l = cntab + cntac + cntba + cntbc + cntca + cntcb;
	l = 2 * l;
	l /= 3;
	ans += l;
	return ans;
}

• Subtask 1: 21 / 21
• Subtask 2: 22 / 22
• Subtask 3: 13 / 13
• Subtask 4: 28 / 28
• Subtask 5: 16 / 16