Submission #490541

#	Time	Username	Problem	Language	Result	Execution time	Memory
490541		sliviu	Mutating DNA (IOI21_dna)	C++17	100 / 100	35 ms	7412 KiB

dna

#include <bits/stdc++.h>

using namespace std;

int n, c[100001][3][3];

int val(char x) {
	return x == 'A' ? 0 : x == 'T' ? 1 : 2;
}

void init(string a, string b) {
	n = a.length();
	for (int i = 0; i < n; ++i) {
		++c[i + 1][val(a[i])][val(b[i])];
		for (int j = 0; j < 3; ++j)
			for (int k = 0; k < 3; ++k)
				c[i + 1][j][k] += c[i][j][k];
	}
}

int get_distance(int x, int y) {
	int left = y - x + 1, swaps = 0;
	int cur[3][3];
	for (int i = 0; i < 3; ++i)
		for (int j = 0; j < 3; ++j)
			cur[i][j] = c[y + 1][i][j] - c[x][i][j];
	for (int i = 0; i < 3; ++i)
		left -= cur[i][i];
	for (int i = 0; i < 3; ++i)
		for (int j = i + 1; j < 3; ++j) {
			int off = min(cur[i][j], cur[j][i]);
			cur[i][j] -= off, cur[j][i] -= off;
			left -= 2 * off, swaps += off;
		}
	int a = n, b = n;
	for (int i = 0; i < 3; ++i)
		a = min(a, cur[i][(i + 1) % 3]), b = min(b, cur[(i + 1) % 3][i]);
	for (int i = 0; i < 3; ++i)
		cur[i][(i + 1) % 3] -= a, cur[(i + 1) % 3][i] -= b;
	left -= 3 * (a + b), swaps += 2 * (a + b);
	if (left)
		return -1;
	return swaps;
}

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