Submission #345960

#	Time	Username	Problem	Language	Result	Execution time	Memory
345960		Alma	Combo (IOI18_combo)	C++14	100 / 100	44 ms	696 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
    }
    // if N = 1...
    if (N == 1) {return S;}

    // guess from 2nd letter to N-1 (num of calls to "press" = N-2)
    while ((int)S.length() < N-1) {
        int i = (int)S.length();
        p = S + v[0]+v[0] + S + v[0]+v[1] + S + v[0]+v[2] + S + v[1];
        // f.e. 1st = A      p = SBB SBX SBY SX
        
        coins = press(p);
        if (coins == i+2) {S += v[0];}        // next letter = B  v[0]
        else if (coins == i+1) {S += v[1];}   // next letter = X  v[1]
        else {S += v[2];}                     // next letter = Y  v[2]
        i++;
    }

    // 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