Submission #713112

#	Time	Username	Problem	Language	Result	Execution time	Memory
713112		tht2005	Combo (IOI18_combo)	C++17	100 / 100	62 ms	616 KiB

combo

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

using namespace std;

string tmp[100];

int solve(int l, int r) {
    if(l == r) {
        return l;
    }
    int m = (l + r) >> 1;
    string combo;
    for(int i = m + 1; i <= r; ++i) {
        for(char ch : tmp[i]) {
            combo.push_back(ch);
        }
    }
    if(press(combo) >= (int)tmp[0].size()) {
        return solve(m + 1, r);
    }
    return solve(l, m);
}

string guess_sequence(int N) {
    string BUTTONS = "ABXY";
    for(int i = 0; i < 4; ++i) {
        tmp[i] = BUTTONS[i];
    }
    int first_button = solve(0, 3);
    swap(BUTTONS[3], BUTTONS[first_button]);
    string res(1, BUTTONS[3]);
    for(int i = 2; i < N; ++i) {
        string ask = res;
        ask.push_back(BUTTONS[0]);
        for(int j = 0; j < 3; ++j) {
            for(char ch : res) {
                ask.push_back(ch);
            }
            ask.push_back(BUTTONS[1]);
            ask.push_back(BUTTONS[j]);
        }
        int o = press(ask);
        if(o == i) {
            res.push_back(BUTTONS[0]);
        }
        else if(o == i + 1) {
            res.push_back(BUTTONS[1]);
        }
        else {
            res.push_back(BUTTONS[2]);
        }
    }
    if(N > 1) {
        int last = 0;
        for(int ch = 1; ch < 3; ++ch) {
            string ask = res;
            ask.push_back(BUTTONS[ch]);
            if(press(ask) == N) {
                last = ch;
                break;
            }
        }
        res.push_back(BUTTONS[last]);
    }
    return res;
}

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