Submission #1142711

#	Time	Username	Problem	Language	Result	Execution time	Memory
1142711		mifo	Combo (IOI18_combo)	C++20	100 / 100	7 ms	508 KiB

combo

#include "bits/stdc++.h"
#include "combo.h"

using namespace std;

std::string guess_sequence(int n) {
    string pb = "ABXY";
    string possibilities = "";
    string p = "";

    // prefix : all good
    if (press("AB") > 0) {
      if (press("A") == 1) {
        p += 'A';
      } else {
        p += 'B';
      }
    }
    else if (press("X") == 1) {
      p += 'X';
    }
    else {
      p += 'Y';
    }

    for (int i=0; i<pb.size(); ++i) {
      if (pb[i] == p[0]) {
        continue;
      }
      possibilities+=pb[i];
    }

    // middle string : problem might be here
    int last_ans = 1;
    while(last_ans<n-1)
    {
      string toAdd = "";

      toAdd+=possibilities[0];


      for(int i=0; i<possibilities.size(); ++i) {
        toAdd+=p;
        toAdd+=possibilities[1];
        toAdd+=possibilities[i];
      }

      int ans = press(p + toAdd);
      if (ans-last_ans==1) {
        p+=possibilities[0];
      } else if (ans-last_ans > 1) {
        p+=possibilities[1];
      } else {
        p+=possibilities[2];
      }

      ++last_ans;
    }
    if(n==1)return p;
    // last char : normally all good
    if(press(p + possibilities[0]) == n) {
      p+=possibilities[0];
    }
    else if(press(p + possibilities[1]) == n) {
      p+=possibilities[1];
    }
    else {
      p+=possibilities[2];
    }

    return p;
}

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