Submission #581644

#	Time	Username	Problem	Language	Result	Execution time	Memory
581644		penguinhacker	Mutating DNA (IOI21_dna)	C++17	100 / 100	50 ms	8944 KiB

dna

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ar array

const int mxN=1e5;
map<char, int> mp;
int cnt1[mxN+1][3], cnt2[mxN+1][3][3], bad[mxN+1];

void init(string a, string b) {
	mp['A']=0, mp['T']=1, mp['C']=2;
	int n=a.size();
	for (int i=0; i<n; ++i) {
		for (int x=0; x<3; ++x) {
			cnt1[i+1][x]=cnt1[i][x]+(mp[a[i]]==x)-(mp[b[i]]==x);
			for (int y=0; y<3; ++y)
				cnt2[i+1][x][y]=cnt2[i][x][y]+(mp[a[i]]==x&&mp[b[i]]==y);
		}
		bad[i+1]=bad[i]+(a[i]!=b[i]);
	}
}

int get_distance(int x, int y) {
	for (int i=0; i<3; ++i)
		if (cnt1[y+1][i]-cnt1[x][i])
			return -1;
	int ans=0, extra=0;
	for (int i=0; i<3; ++i)
		for (int j=i+1; j<3; ++j) {
			int a=cnt2[y+1][i][j]-cnt2[x][i][j];
			int b=cnt2[y+1][j][i]-cnt2[x][j][i];
			ans+=min(a, b);
			extra+=max(a, b)-min(a, b);
		}
	assert(extra%3==0);
	return ans+extra/3*2;
}

/*int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	init("ATACAT", "ACTATA");
	cout << get_distance(1, 3) << " " << get_distance(4, 5) << " " << get_distance(3, 5);
	return 0;
}*/

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