Submission #442955

#	Time	Username	Problem	Language	Result	Execution time	Memory
442955		ltf0501	Mutating DNA (IOI21_dna)	C++17	100 / 100	46 ms	7404 KiB

dna

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

const int kN = 1e5 + 10;
int n, pre[kN][3][3];
map<char, int> mp;
void init(std::string a, std::string b) {
  mp['A'] = 0, mp['T'] = 1, mp['C'] = 2;
  n = a.length();
  for(int i = 0; i < n; i++) {
    if(i) {
      for(int x = 0; x < 3; x++) {
        for(int y = 0; y < 3; y++) pre[i][x][y] = pre[i - 1][x][y];
      }
    }

    pre[i][mp[a[i]]][mp[b[i]]]++;
  }
}

int get_distance(int l, int r) {

  auto Getnum = [&](int x, int y) {
    if(!l) return pre[r][x][y];
    else return pre[r][x][y] - pre[l - 1][x][y];
  };

  int num[3][3] = {};
  for(int i = 0; i < 3; i++) {
    for(int j = 0; j < 3; j++) num[i][j] = Getnum(i, j);
  }

  int cnt = 0;
  for(int i = 0; i < 3; i++) {
    int j = (i + 1) % 3;
    int mn = min(num[i][j], num[j][i]);
    cnt += mn;
    num[i][j] -= mn, num[j][i] -= mn;
  }

  bool flag = 1;
  for(int i = 0; i < 3; i++) flag &= (num[i][(i + 1) % 3] == num[0][1]);
  for(int i = 0; i < 3; i++) flag &= (num[(i + 1) % 3][i] == num[1][0]);

  if(!flag) return -1;
  else {
    cnt += 2 * (num[0][1] + num[1][0]);
    return cnt;
  }
}

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