Submission #393686

#	Time	Username	Problem	Language	Result	Execution time	Memory
393686		phathnv	Combo (IOI18_combo)	C++11	100 / 100	42 ms	572 KiB

combo

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

using namespace std;

string guess_sequence(int n) {
    char ch[4] = {'A', 'B', 'X', 'Y'};
    int l = 0, r = 3;
    while (l < r){
        int mid = (l + r) >> 1;
        string tmp;
        for(int i = l; i <= mid; i++)
            tmp.push_back(ch[i]);
        if (press(tmp) > 0)
            r = mid;
        else
            l = mid + 1;
    }
    swap(ch[3], ch[l]);
    string s;
    s.push_back(ch[3]);
    for(int i = 2; i < n; i++){
        string tmp = s + ch[1] + s + ch[2] + ch[0] + s + ch[2] + ch[1] + s + ch[2] + ch[2];
        s.push_back(ch[press(tmp) - i + 1]);
    }
    if ((int) s.size() == n)
        return s;
    if (press(s + ch[0]) == n)
        s.push_back(ch[0]);
    else if (press(s + ch[1]) == n)
        s.push_back(ch[1]);
    else
        s.push_back(ch[2]);

    return s;
}

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