Submission #1145629

#	Time	Username	Problem	Language	Result	Execution time	Memory
1145629		guagua0407	Combo (IOI18_combo)	C++20	100 / 100	7 ms	508 KiB

combo

#include "combo.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

std::string guess_sequence(int n) {
    string str;
    char st;
    vector<char> cs={'X','Y'};
    if(press("XY")==0) cs={'A','B'};
    st=cs[0];
    if(press(string(1,cs[0]))==0) st=cs[1];
    vector<char> cand;
    for(auto c:{'X','Y','A','B'}){
        if(c!=st) cand.push_back(c);
    }
    str+=st;
    for(int i=2;i<n;i++){
        string p;
        p+=(str+cand[0]+cand[0]);
        p+=(str+cand[0]+cand[1]);
        p+=(str+cand[0]+cand[2]);
        p+=(str+cand[1]);
        int res=press(p);
        if(res==i+1) str+=cand[0];
        else if(res==i) str+=cand[1];
        else str+=cand[2];
    }
    if(n==1) return str;
    cs={cand[0],cand[1]};
    if(press(str+cand[0]+str+cand[1])==n){
        st=cand[0];
        if(press(str+cand[0])!=n) st=cand[1];
    }
    else{
        st=cand[2];
    }
    str+=st;
    //cout<<str<<'\n';
    return str;
}

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