Submission #841568

#	Time	Username	Problem	Language	Result	Execution time	Memory
841568		tigran	Mutating DNA (IOI21_dna)	C++17	100 / 100	252 ms	5988 KiB

dna

#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
 
#define ll long long
 
const int N = 1e5 + 5;
 
int same[N];
int n;
vector<int> wa[3], wb[3];
map<string, vector<int>> mp;
 
int get_range(const vector<int>& vec, int l, int r){
	return upper_bound(vec.begin(), vec.end(), r) - lower_bound(vec.begin(), vec.end(), l);
}
 
void init(std::string a, std::string b) {
	n = a.size();
	for (int i = 0; i < n; i++) same[i] = (a[i] == b[i]);
	for (int i = 0; i < n; i++) same[i] += same[i-1];
 
	for (int i = 0; i < n; i++){
		if (a[i] == 'A') wa[0].push_back(i);
		else if (a[i] == 'C') wa[1].push_back(i);
		else wa[2].push_back(i);
	}
 
	for (int i = 0; i < n; i++){
		if (b[i] == 'A') wb[0].push_back(i);
		else if (b[i] == 'C') wb[1].push_back(i);
		else wb[2].push_back(i);
	}
 
	for (int i = 0; i < n; i++){
		string s; s.append(1, a[i]); s.append(1, b[i]);
		mp[s].push_back(i);
	}
}
 
int get_distance(int x, int y) {
	bool ok = true;
	for (int i = 0; i < 3; i++){
		int c1 = get_range(wa[i], x, y);
		int c2 = get_range(wb[i], x, y);
 
		if (c1 != c2) {ok = false; break;}
	}
 
	if (!ok) return -1;
	int len = y-x+1, ans = 0, res;
 
	res = min(get_range(mp["AC"], x, y), get_range(mp["CA"], x, y)); ans += res; len -= 2 * res;
	res = min(get_range(mp["AT"], x, y), get_range(mp["TA"], x, y)); ans += res; len -= 2 * res;
	res = min(get_range(mp["CT"], x, y), get_range(mp["TC"], x, y)); ans += res; len -= 2 * res;
 
	int s = (same[y] - ((x-1 < 0)? 0: same[x-1]));
	len -= s;
	return ans + len/3*2;
 
 
 
}

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