Submission #867358

#	Time	Username	Problem	Language	Result	Execution time	Memory
867358		sleepntsheep	Aliens (IOI07_aliens)	C++17	80 / 100	3087 ms	704 KiB

aliens

#include <iostream>
#include <map>
#include <cassert>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <utility>
#include <array>

using namespace std;
#define ALL(x) x.begin(), x.end()
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false);
using ll = long long;

int m, n, x, y, bl, bt, br;
map<pair<int, int>, bool> mp;

bool examine(int x, int y)
{
    if (mp.count({x, y})) return mp[{x, y}];
    if (x < 1 || x > n || y < 1 || y > n) return false;
    cout << "examine " << x << ' ' << y << '\n' << flush;
    char s[6]{0};
    cin >> s;
    return mp[{x, y}] = (s[0] == 't');
}

void solution(int x, int y)
{
    cout << "solution " << x << ' ' << y << "\n" << flush;
    exit(0);
}

void find_border()
{
    bl = -1; bt = -1; br =-1;
    int l = 0, r = x-1;
    while (l <= r)
    {
        int o = (l+r)/2;
        if (examine(o, y))
        {
            int oo = (o+x)/2;
            if (examine(oo, y)) 
            {
                int ooo = (oo+x)/2;
                if (examine(ooo, y)) r = o - 1;
                else l = ooo + 1, bl = ooo;
            }
            else l = oo + 1, bl = oo;
        }
        else l = o + 1, bl = o;
    }

    l = x+1, r = n+1;
    while (l <= r)
    {
        int o = (l+r)/2;
        if (examine(o, y))
        {
            int oo = (l+o)/2;
            if (examine(oo, y))
            {
                int ooo = (oo + l) / 2;
                if (examine(ooo, y)) l = o + 1;
                else r = min(ooo - 1, r-1), br = ooo;
            }
            else r = oo - 1, br = oo;
        }
        else r = o - 1, br = o;
    }
    assert(!examine(br, y) && examine(br-1, y));

    m = br - bl - 1;

    l = 0, r = y - 1;
    while (l <= r)
    {
        int o = (l+r)/2;
        if (examine(x, o))
        {
            int oo = (o+y)/2;
            if (examine(x, oo))
            {
                int ooo = (oo+y)/2;
                if (examine(x, ooo)) r = o - 1;
                else l = ooo + 1, bt = ooo;
            }
            else l = oo + 1, bt = oo;
        }
        else l = o + 1, bt = o;
    }
    x = bl + 1; y = bt + 1;
}

void find_11()
{
    for (; x>2*m && examine(x-2*m, y); x-=2*m);
    for (; y>2*m && examine(x, y-2*m); y-=2*m);
    for (; x>m&&y>m&&examine(x-m, y-m); x-=m, y-=m);
}

void find_middle()
{
    x += 2*m, y += 2*m;
    x += m/2, y += m/2;
}

int main()
{
    ShinLena;
    cin >> n >> x >> y;
    find_border();
    find_11();
    find_middle();
    solution(x, y);
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10