Submission #783715

#	Time	Username	Problem	Language	Result	Execution time	Memory
783715		mousebeaver	Mutating DNA (IOI21_dna)	C++17	100 / 100	34 ms	8952 KiB

dna

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

const int N = 100000;
int diff[N];
int Aa[N];
int Ca[N];
int Ab[N];
int Cb[N];

int ind(char c)
{
	if(c == 'A')
	{
		return 0;
	}
	else if(c == 'C')
	{
		return 1;
	}
	return 2;
}

int adjlist[N][3][3]; //Letter string a, letter string b

void init(std::string a, std::string b) 
{
	Aa[0] = (a[0] == 'A');
	Ca[0] = (a[0] == 'C');
	Ab[0] = (b[0] == 'A');
	Cb[0] = (b[0] == 'C');
	for(int c = 0; c < 3; c++)
	{
		for(int d = 0; d < 3; d++)
		{
			adjlist[0][c][d] = 0;
		}
	}
	adjlist[0][ind(a[0])][ind(b[0])] = 1;

	int n = a.length();
	for(int i = 1; i < n; i++)
	{
		Aa[i] = Aa[i-1]+(a[i] == 'A');
		Ca[i] = Ca[i-1]+(a[i] == 'C');
		Ab[i] = Ab[i-1]+(b[i] == 'A');
		Cb[i] = Cb[i-1]+(b[i] == 'C');

		for(int c = 0; c < 3; c++)
		{
			for(int d = 0; d < 3; d++)
			{
				adjlist[i][c][d] = adjlist[i-1][c][d];
			}
		}
		adjlist[i][ind(a[i])][ind(b[i])]++;
	}
}

int get_distance(int x, int y) 
{
	if(Aa[y] - (x == 0 ? 0 : Aa[x-1]) != Ab[y] - (x== 0 ? 0 : Ab[x-1]) ||
		Ca[y] - (x == 0 ? 0 : Ca[x-1]) != Cb[y] - (x== 0 ? 0 : Cb[x-1]))
	{
		return -1;
	}

	int counter[3][3];
	for(int c = 0; c < 3; c++)
	{
		for(int d = 0; d < 3; d++)
		{
			counter[c][d] = adjlist[y][c][d] - (x == 0 ? 0 : adjlist[x-1][c][d]);
		}
	}

	int output = 0;
	for(int i = 0; i < 3; i++)
	{
		counter[i][i] = 0;
		for(int j = 0; j < 3; j++)
		{
			if(i == j) continue;
			int m = min(counter[i][j], counter[j][i]);
			counter[i][j] -= m;
			counter[j][i] -= m;
			output += m;
		}
	}

	output += max(counter[0][1], counter[0][2])*2;
	
	return output;
}

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