Submission #835096

#	Time	Username	Problem	Language	Result	Execution time	Memory
835096		Johann	Combo (IOI18_combo)	C++14	100 / 100	23 ms	576 KiB

combo

#include "combo.h"
#include "bits/stdc++.h"
using namespace std;

typedef vector<int> vi;
typedef vector<vi> vvi;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

string guess_sequence(int N)
{
  string p;
  p = "AB";
  string start;
  if (press(p))
    start = (press("A")) ? "A" : "B";
  else
    start = (press("X")) ? "X" : "Y";

  if (N == 1)
    return start;

  vector<char> remaining = {'A', 'B', 'X', 'Y'};
  for (int i = 0; i < 3; ++i)
    if (remaining[i] == start[0])
      swap(remaining[i], remaining.back());
  remaining.pop_back();

  for (int i = 1; i < N - 1; ++i)
  {
    p = "";
    p += start + remaining[0];
    for (int j = 0; j < 3; ++j)
      p += start + remaining[1] + remaining[j];

    int tmp = press(p) - i;
    if (tmp == 0)
      start += remaining[2];
    else if (tmp == 1)
      start += remaining[0];
    else if (tmp == 2)
      start += remaining[1];
    else
      assert(false);
  }

  if (press(start + remaining[0]) == N)
    start += remaining[0];
  else if (press(start + remaining[1]) == N)
    start += remaining[1];
  else
    start += remaining[2];

  assert(sz(start) == N);

  return start;
}

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95