Submission #466317

#	Time	Username	Problem	Language	Result	Execution time	Memory
466317		popovicirobert	Mutating DNA (IOI21_dna)	C++17	100 / 100	53 ms	7444 KiB

dna

#include "dna.h"
#include <bits/stdc++.h>

using namespace std;

constexpr int N = (int)1e5;
constexpr int SIGMA = 256;

static int freq[N + 1][3][3];
static int id[SIGMA];
static int n;

void init(std::string a, std::string b) {
	id['A'] = 0;
	id['C'] = 1;
	id['T'] = 2;

	n = a.size();
	a = " " + a;
	b = " " + b;

	for (int i = 1; i <= n; i++) {
		for (int x = 0; x < 3; x++) {
			for (int y = 0; y < 3; y++) {
				freq[i][x][y] = freq[i - 1][x][y] + (id[a[i]] == x && id[b[i]] == y);
			}
		}
	}
}

int get_distance(int x, int y) {
	x++, y++;

	static int currFreq[3][3];
	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 3; j++) {
			currFreq[i][j] = freq[y][i][j] - freq[x - 1][i][j];
			// cerr << currFreq[i][j] << " ";
		} 
		// cerr << "\n";
	}
	// cerr << "\n";

	int answer = 0;
	auto Update = [&answer](int id1, int id2) {
		int curr = min(currFreq[id1][id2], currFreq[id2][id1]);
		currFreq[id1][id2] -= curr;
		currFreq[id2][id1] -= curr;
		answer += curr;
	};

	Update(0, 1);
	Update(1, 2);
	Update(0, 2);

	if (currFreq[0][1] != currFreq[1][2] || currFreq[1][2] != currFreq[2][0] ||
		currFreq[0][2] != currFreq[2][1] || currFreq[2][1] != currFreq[1][0]) {
		return -1;
	}

	int mx = 0;
	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 3; j++) {
			if (i != j) {
				mx = max(mx, currFreq[i][j]);
			}
		}
	}
	answer += 2 * mx;
	// cerr << "DEBUG: " << mx << "\n";

	return answer;
}

Compilation message (stderr)

dna.cpp: In function 'void init(std::string, std::string)':
dna.cpp:25:49: warning: array subscript has type 'char' [-Wchar-subscripts]
   25 |     freq[i][x][y] = freq[i - 1][x][y] + (id[a[i]] == x && id[b[i]] == y);
      |                                                 ^
dna.cpp:25:66: warning: array subscript has type 'char' [-Wchar-subscripts]
   25 |     freq[i][x][y] = freq[i - 1][x][y] + (id[a[i]] == x && id[b[i]] == y);
      |                                                                  ^

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