Submission #705562

#	Time	Username	Problem	Language	Result	Execution time	Memory
705562		jakobrs	Mutating DNA (IOI21_dna)	C++17	100 / 100	36 ms	5384 KiB

dna

#include <iostream>
#include <vector>

struct Count {
  int at, ca, tc;
  int qw;

  Count() : at(0), ca(0), tc(0), qw(0) {}

  inline Count operator-(Count rhs) const {
    Count result = *this;
    result.at -= rhs.at;
    result.ca -= rhs.ca;
    result.tc -= rhs.tc;
    result.qw -= rhs.qw;
    return result;
  }
};

std::vector<Count> prefixes;

void init(std::string a, std::string b) {
  prefixes.reserve(a.size() + 1);
  Count count;
  prefixes.push_back(count);
  for (size_t i = 0; i < a.size(); i++) {
    if (a[i] == 'A' && b[i] == 'T') count.at += 1;
    if (a[i] == 'T' && b[i] == 'A') count.at -= 1;
    if (a[i] == 'C' && b[i] == 'A') count.ca += 1;
    if (a[i] == 'A' && b[i] == 'C') count.ca -= 1;
    if (a[i] == 'T' && b[i] == 'C') count.tc += 1;
    if (a[i] == 'C' && b[i] == 'T') count.tc -= 1;
    if (a[i] != b[i]) count.qw += 1;
    prefixes.push_back(count);
  }
}

int get_distance(int x, int y) {
  y += 1;

  Count count = prefixes[y] - prefixes[x];

  if (!(count.at == count.ca && count.ca == count.tc)) return -1;

  return (count.qw + std::abs(count.at)) / 2;
}

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