Submission #388347

#	Time	Username	Problem	Language	Result	Execution time	Memory
388347		warner1129	Combo (IOI18_combo)	C++17	Compilation error	0 ms	0 KiB

combo

#// define local

#ifdef local
#include <bits/stdc++.h>
using namespace std;
int press(string p) {
	cout << p;
	int ret;
	cin >> ret;
	return ret;
}
string guess_sequence(int);
signed main() {
	int n;
	cin >> n;
	cout << guess_sequence(n) << '\n';
	return 0;
}
#endif

string guess_sequence(int n) {
	string ans, tmp;
	int ret, len = 1;
	ret = press("AB");
	if (ret == 1) {
		ret = press("A");
		if (ret == 1) ans = "A";
		else ans = "B";
	}	
	else {
		ret = press("X");
		if (ret == 1) ans = "X";
		else ans = "Y";
	}
	vector<string> L;
	if ("A" != ans) L.push_back("A");
	if ("B" != ans) L.push_back("B");
	if ("X" != ans) L.push_back("X");
	if ("Y" != ans) L.push_back("Y");
	string P[4];
	P[0] = L[0] + L[0], P[1] = L[0] + L[1], P[2] = L[0] + L[2];
	P[3] = L[1];
	for (int i = 2; i < n; i++) {
		tmp = "";
		for (int j = 0; j < 4; j++)
			tmp += (ans + P[j]);
		ret = press(tmp);
		if (ret == len + 2) ans += L[0];
		else if (ret == len + 1) ans += L[1];
		else if (ret == len) ans += L[2];
		len++;
	}
	ret = press(ans + L[0] + ans + L[1]);
	if (ret == len+1) {
		ret = press(ans + L[0]);
		if (ret == len+1) ans += L[0];
		else ans += L[1];
	}
	else if (ret == len)
		ans += L[2];
	assert(ans.size() == n);
	return ans;	
}

Compilation message (stderr)

combo.cpp:21:1: error: 'string' does not name a type
   21 | string guess_sequence(int n) {
      | ^~~~~~