Submission #483011

#	Time	Username	Problem	Language	Result	Execution time	Memory
483011		Spade1	Combo (IOI18_combo)	C++14	100 / 100	36 ms	640 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
#define ll long long
#define pii pair<int, int>
#define st first
#define nd second
#define pb push_back
using namespace std;

string guess_sequence(int N) {
    char first;
    if (press("AB")) {
        if (press("A")) first = 'A';
        else first = 'B';
    }
    else {
        if (press("X")) first = 'X';
        else first = 'Y';
    }

    if(N == 1){
		string tmp(1, first);
		return tmp;
	}

    string ans(N, first);
    string s(4*N, first);
    vector<char> rem;

    if (first != 'A') rem.pb('A');
    if (first != 'B') rem.pb('B');
    if (first != 'X') rem.pb('X');
    if (first != 'Y') rem.pb('Y');

    for (int i = 1; i < N - 1; ++i) {
        s[i] = rem[0];
        s[N + i] = rem[0];
        s[2*N + i] = rem[0];
        s[3*N + i] = rem[1];

        s[i + 1] = rem[0];
        s[N + i + 1] = rem[1];
        s[2*N + i + 1] = rem[2];

        int ret = press(s), c;
        if (ret == i) c = 2;
        if (ret == i + 1) c = 1;
        if (ret == i + 2) c = 0;
        s[i] = rem[c];
        s[N + i] = rem[c];
        s[2*N + i] = rem[c];
        s[3*N + i] = rem[c];
        ans[i] = rem[c];
    }

    ans[N - 1] = rem[0];
    if (press(ans) == N) return ans;
    ans[N - 1] = rem[1];
    if (press(ans) == N) return ans;
    ans[N - 1] = rem[2];
    return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:49:21: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   49 |         s[i] = rem[c];
      |                     ^

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