Submission #880112

#	Time	Username	Problem	Language	Result	Execution time	Memory
880112		AkibAzmain	Mutating DNA (IOI21_dna)	C++17	100 / 100	64 ms	6000 KiB

dna

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

int n;
vector < array < int, 6 > > ps;

int
toi (char x, char y)
{
  if (y > x) --y;
  return (x - 'A') * 2 + y - 'A';
}

auto
brs (int i, int l, int r)
{
  int ans = ps[r][i];
  if (l) ans -= ps[l - 1][i];
  return ans;
}

void init(std::string a, std::string b) {
  n = a.size ();
  ps.resize (n);
  for (int i = 0; i < n; ++i)
    {
      if (a[i] == 'T') a[i] = 'B';
      if (b[i] == 'T') b[i] = 'B';
      if (i) ps[i] = ps[i - 1];
      if (a[i] != b[i]) ps[i][toi (a[i], b[i])]++;
    }
}

int get_distance(int x, int y) {
  array < int, 6 > a = { brs (0, x, y), brs (1, x, y), brs (2, x, y),
                         brs (3, x, y), brs (4, x, y), brs (5, x, y) };
  int c = 0;
  auto fn = [&] ()
  {
    for (char x = 'A'; x <= 'C'; ++x)
      for (char y = 'A'; y <= 'C'; ++y)
        if (x != y)
          {
            int m = min (a[toi (x, y)], a[toi (y, x)]);
            c += m;
            a[toi (x, y)] -= m;
            a[toi (y, x)] -= m;
          }
  };
  fn ();
  for (char x = 'A'; x <= 'C'; ++x)
    for (char y = 'A'; y <= 'C'; ++y)
      if (x != y)
        {
          char z = 'A' + 'B' + 'C' - x - y;
          int m = min (a[toi (x, y)], a[toi (z, x)]);
          c += m;
          a[toi (x, y)] -= m;
          a[toi (z, x)] -= m;
          a[toi (z, y)] += m;
          fn ();
        }
  if (a[0] || a[1] || a[2] || a[3] || a[4] || a[5]) return -1;
  return c;
}

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