Submission #1123233

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123233		blackslex	Mutating DNA (IOI21_dna)	C++20	100 / 100	157 ms	45944 KiB

dna

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

using namespace std;

int n;
string s, t;
vector<map<char, int>> prefs, preft;
vector<vector<int>> cnt;

int get (int l, int r, vector<map<char, int>> &pref, char c) {
	return pref[r][c] - (l ? pref[l - 1][c] : 0);
}

void init(std::string a, std::string b) {
	s = a; t = b;
	n = a.size();
	prefs.resize(n);
	preft.resize(n);
	cnt.resize(n, vector<int>(6));
	for (int i = 0; i < n; i++) {
		prefs[i][s[i]]++;
		preft[i][t[i]]++;
		if (s[i] == 'A') {
			if (t[i] == 'T') cnt[i][0]++;
			if (t[i] == 'C') cnt[i][2]++;
		}
		if (s[i] == 'T') {
			if (t[i] == 'A') cnt[i][1]++;
			if (t[i] == 'C') cnt[i][4]++;
		}
		if (s[i] == 'C') {
			if (t[i] == 'A') cnt[i][3]++;
			if (t[i] == 'T') cnt[i][5]++;
		}
	}
	for (int i = 1; i < n; i++) {
		for (auto e: {'A', 'T', 'C'}) {
			prefs[i][e] += prefs[i - 1][e];
			preft[i][e] += preft[i - 1][e];
		}
		for (int j = 0; j < 6; j++) cnt[i][j] += cnt[i - 1][j];
	}
}

int get_distance(int x, int y) {
	for (auto e: {'A', 'T', 'C'}) {
		if (get(x, y, prefs, e) != get(x, y, preft, e)) return -1;
	}
	int ans = 0;
	vector<int> cur(6);
	for (int i = 0; i < 6; i++) {
		cur[i] = cnt[y][i] - (x ? cnt[x - 1][i] : 0);
	}
	for (int i = 0; i < 6; i += 2) {
		int c = min(cur[i], cur[i + 1]);
		ans += c;
		cur[i] -= c;
		cur[i + 1] -= c;
	}
	ans += (cur[0] + cur[1]) * 2;
	return ans;
}

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