Submission #506008

#	Time	Username	Problem	Language	Result	Execution time	Memory
506008		LouayFarah	Combo (IOI18_combo)	C++14	5 / 100	1 ms	200 KiB

combo

#include "bits/stdc++.h"

using namespace std;

#define endl "\n"
#define ll long long int
#define pb push_back
#define mp make_pair
#define fi first
#define se second

const long long MOD = 1e9+7;
const long long INF = 1e18;

int nx[4] = {0, 0, -1, 1};
int ny[4] = {1, -1, 0, 0};

ll my_rand(ll l, ll r)
{
    srand(chrono::steady_clock::now().time_since_epoch().count());

    ll len = r-l;
    ll a = rand()%len;
    ll b = rand()%len;

    ll res = ((((a%len)*((RAND_MAX+1)%len))%len) + (b%len))%len;

    if(res<l)
        res +=l;

    return res;
}

int press(string p);

string guess_sequence(int n)
{
    string s = "";
    string choices = "ABXY";

    string p = "";
    vector<bool> visited(4, false);
    while(true)
    {
        ll x = my_rand(0, 4);
        if(visited[x])
            continue;
        visited[x] = true;
        p.pb(choices[x]);
        if(press(p)==1)
        {
            s = p;
            break;
        }
        p = s;
    }

    while(int(s.length())<n)
    {
        ll i = my_rand(0, 4);
        if(choices[i]==s[0])
            continue;
        if(choices[i]==s[int(s.length())-1])
            continue;

        p = s;
        while(int(p.length())<4*n)
        {
            p.pb(choices[i]);
        }

        ll added = press(p) - int(s.length());
        p = s;

        if(added>0)
        {
            for(int j = 0; j<added; j++)
                s.pb(choices[i]);
        }
        else
        {
            char c = 'A';
            for(int k = 0; k<4; i++)
            {
                if(choices[k]!=choices[i]&&choices[k]!=s[0]&&choices[k]!=s[int(s.length())-1])
                {
                    c = choices[k];
                    break;
                }
            }

            while(int(p.length())<4*n)
            {
                p.pb(c);
            }

            ll ad = press(p)-int(s.length());
            for(int k = 0; k<ad; k++)
                s.pb(c);
        }

    }

    return s;
}

Compilation message (stderr)

combo.cpp: In function 'long long int my_rand(long long int, long long int)':
combo.cpp:26:35: warning: integer overflow in expression of type 'int' results in '-2147483648' [-Woverflow]
   26 |     ll res = ((((a%len)*((RAND_MAX+1)%len))%len) + (b%len))%len;
      |                                   ^

• Subtask 1: 5 / 5
• Subtask 2: 0 / 95