Submission #728466

#	Time	Username	Problem	Language	Result	Execution time	Memory
728466		MBI	Combo (IOI18_combo)	C++17	100 / 100	28 ms	580 KiB

combo

#include "combo.h"
// #include <iostream>

using namespace std;
string guess_sequence(int N) {
	int l=1,k;
	string s;
	if (press("AB")>=1){
		if (press("A")) s="A";
		else s="B";
	}
	else {
		if (press("X")) s="X";
		else s="Y";
	}
	if (s=="A"){
		while (l<N){
			if (l==N-1){
				k=press(s+"B"+s+"X");
				if (k==N){
					if (press(s+"B")==N) s+="B";
					else s+="X";
				}
				else s+="Y";
				break;
			}
			k=press(s+"B"+s+"XB"+s+"XX"+s+"XY");
			if (k==l) {
				s+="Y";
				l++;
			}
			if (k==l+1){
				s+="B";
				l++;
			}
			if (k==l+2){
				s+="X";
				l++;
			}
		}
	}
	else if (s=="B"){
		while (l<N){
			if (l==N-1){
				k=press(s+"A"+s+"X");
				if (k==N){
					if (press(s+"A")==N) s+="A";
					else s+="X";
				}
				else s+="Y";
				break;
			}
			k=press(s+"A"+s+"XA"+s+"XX"+s+"XY");
			if (k==l) {
				s+="Y";
				l++;
			}
			if (k==l+1){
				s+="A";
				l++;
			}
			if (k==l+2){
				s+="X";
				l++;
			}
		}
	}
	else if (s=="X"){
		while (l<N){
			if (l==N-1){
				k=press(s+"B"+s+"A");
				if (k==N){
					if (press(s+"B")==N) s+="B";
					else s+="A";
				}
				else s+="Y";
				break;
			}
			k=press(s+"B"+s+"AB"+s+"AA"+s+"AY");
			if (k==l) {
				s+="Y";
				l++;
			}
			if (k==l+1){
				s+="B";
				l++;
			}
			if (k==l+2){
				s+="A";
				l++;
			}
		}
	}
	else {
		while (l<N){
			if (l==N-1){
				k=press(s+"B"+s+"X");
				if (k==N){
					if (press(s+"B")==N) s+="B";
					else s+="X";
				}
				else s+="A";
				break;
			}
			k=press(s+"B"+s+"XB"+s+"XX"+s+"XA");
			if (k==l) {
				s+="A";
				l++;
			}
			if (k==l+1){
				s+="B";
				l++;
			}
			if (k==l+2){
				s+="X";
				l++;
			}
		}
	}
	// cerr << s << " \n";
	return s;
}

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