Submission #144521

#	Time	Username	Problem	Language	Result	Execution time	Memory
144521		arnold518	Combo (IOI18_combo)	C++14	100 / 100	66 ms	624 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2000;

int N;
char S, P, Q, R;
string ans;

string guess_sequence(int _N)
{
	int i, j;
	N=_N;

	string t; int res;
	t=string(N, 'A')+string(N, 'B'); res=press(t);

	if(res>0)
	{
		t=string(N, 'A'); res=press(t);
		if(res>0) S='A', P='B', Q='X', R='Y';
		else S='B', P='A', Q='X', R='Y';
	}
	else
	{
		t=string(N, 'X'); res=press(t);
		if(res>0) S='X', P='Y', Q='A', R='B';
		else S='Y', P='X', Q='A', R='B';	
	}
	ans+=S;
	if(N==1) return ans;

	for(i=2; i<N; i++)
	{
		t=ans+P+P+ans+P+Q+ans+P+R+ans+Q; res=press(t);
		if(res==ans.size()+2) ans+=P;
		else if(res==ans.size()+1) ans+=Q;
		else ans+=R;
	}

	t=ans+P; res=press(t);
	if(res==N) ans+=P;
	else
	{
		t=ans+Q; res=press(t);
		if(res==N) ans+=Q;
		else ans+=R;
	}
	return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:41:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |   if(res==ans.size()+2) ans+=P;
      |      ~~~^~~~~~~~~~~~~~
combo.cpp:42:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |   else if(res==ans.size()+1) ans+=Q;
      |           ~~~^~~~~~~~~~~~~~
combo.cpp:17:9: warning: unused variable 'j' [-Wunused-variable]
   17 |  int i, j;
      |         ^

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