Submission #345947

#	Time	Username	Problem	Language	Result	Execution time	Memory
345947		BlancaHM	Combo (IOI18_combo)	C++14	100 / 100	49 ms	672 KiB

combo

#include <iostream>
#include <vector>
#include <string>
#include <combo.h>
using namespace std;
 
string guess_sequence(int N) {
 
    // 100 points: N + 2 calls to "press"
    string p = "";
    string S = "";
    vector<string> v = {};
    int coins = 0;
 
    // guess 1st letter of S (num of calls to "press" = 2)
    p = "AB"; coins = press(p);
    if (coins >= 1) {
        p = "A"; coins = press(p);
        if (coins == 1) {S = "A"; v = {"B", "X", "Y"};}  // 1st letter = A
        else {S = "B"; v = {"A", "X", "Y"};}             // 1st letter = B
    }
    else {
        p = "X"; coins = press(p);
        if (coins == 1) {S = "X"; v = {"A", "B", "Y"};}  // 1st letter = X
        else {S = "Y"; v = {"A", "B", "X"};}             // 1st letter = Y
    }
 
    // guess from 2nd letter to N-1 (num of calls to "press" = N-2)
    while (3*((int) S.length() + 2) + (int) S.length() + 1 <= 4*N) {
        p = S + v[0]+v[0] + S + v[0]+v[1] + S + v[0]+v[2] + S + v[1];
        coins = press(p);
        if (coins == (int) S.length() +2) {S += v[0];}        // next letter = B  v[0]
        else if (coins == (int) S.length() +1) {S += v[1];}   // next letter = X  v[1]
        else {S += v[2];}                     // next letter = Y  v[2]
    }
 	if ((int) S.length() < N) {
      // guess last letter of S (num of calls to "press" = 2)
      p = S + v[0];
      coins = press(p);
      if (coins == N) {S += v[0];}
      else {
          p = S + v[1]; coins = press(p);
          if (coins == N) {S += v[1];}
          else {S += v[2];}
      }
    }
    // total of calls to "press" = 2 + N-2 + 2 = (N + 2)
    return S;
}

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