Submission #1176117

#	Time	Username	Problem	Language	Result	Execution time	Memory
1176117		gyg	Mutating DNA (IOI21_dna)	C++20	100 / 100	128 ms	6352 KiB

dna

#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
#define arr array
#define hmap unordered_map
#define mp make_pair
#define fir first
#define sec second
const int N = 1e5 + 5;

int n;
arr<char, N> a, b;

hmap<string, arr<int, N>> sm;
void sm_cmp() {
	for (int i = 1; i <= n; i++) {
		string x = "";
		x += a[i], x += b[i];
		for (string y : {"AA", "AC", "AT", "CC", "CA", "CT", "TT", "TA", "TC"}) {
			sm[y][i] = sm[y][i - 1] + (x == y);
		}
	}
	// for (int i = 1; i <= n; i++)
	// 	cout << i << ": " << sm["AT"][i] << '\n';
}

void init(string _a, string _b) {
	n = _a.size();
	for (int i = 1; i <= n; i++)
		a[i] = _a[i - 1], b[i] = _b[i - 1];

	sm_cmp();
}

int get_distance(int l, int r) {
	l++, r++;
	
	hmap<string, int> cnt;
	for (string x : {"AC", "AT", "CA", "CT", "TA", "TC"}) {
		cnt[x] = sm[x][r] - sm[x][l - 1];
	}
	if (cnt["AT"] + cnt["AC"] != cnt["TA"] + cnt["CA"]) return -1;
	if (cnt["CT"] + cnt["CA"] != cnt["AC"] + cnt["TC"]) return -1;

	int ans = 0;
	for (pair<string, string> x : {mp("AT", "TA"), mp("AC", "CA"), mp("CT", "TC")}) {
		int rmv = min(cnt[x.fir], cnt[x.sec]);
		ans += rmv, cnt[x.fir] -= rmv, cnt[x.sec] -= rmv;
	}

	int mx = 0;
	for (string x : {"AC", "AT", "CA", "CT", "TA", "TC"}) {
		mx = max(mx, cnt[x]);
	}
	ans += 2 * mx;

	return ans;
}

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