Submission #547307

#	Time	Username	Problem	Language	Result	Execution time	Memory
547307		SmolBrain	Aliens (IOI07_aliens)	C++17	100 / 100	2 ms	312 KiB

aliens

// Om Namah Shivaya
// GM in 114 days

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

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

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
template<typename T> void amin(T &a, T b) { a = min(a, b); }
template<typename T> void amax(T &a, T b) { a = max(a, b); }

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

bool query(ll x, ll y) {
    cout << "examine " << x << " " << y << endl;
    string s; cin >> s;
    return s == "true";
}

void solve(int test_case)
{
    // https://www.iarcs.org.in/inoi/online-study-material/problems/aliens-soln.php
    ll n, sx, sy; cin >> n >> sx >> sy;

    ll leftmost = 0, rightmost = 0, bottommost = 0;
    leftmost = sx, rightmost = sx, bottommost = sy;

    ll l = sx, r = sx;

    for (ll curr = 1; curr <= n; curr *= 2) {
        if (sx - curr < 1) {
            l = 1;
            break;
        }

        bool x = query(sx - curr, sy);
        if (!x) {
            l = sx - curr;
            break;
        }

        r = sx - curr;
    }

    while (l <= r) {
        ll mid = (l + r) / 2;
        bool x = query(mid, sy);

        if (x) {
            amin(leftmost, mid);
            r = mid - 1;
        }
        else {
            l = mid + 1;
        }
    }

    l = sx, r = sx;

    for (ll curr = 1; curr <= n; curr *= 2) {
        if (sx + curr > n) {
            r = n;
            break;
        }

        bool x = query(sx + curr, sy);
        if (!x) {
            r = sx + curr;
            break;
        }

        l = sx + curr;
    }

    while (l <= r) {
        ll mid = (l + r) / 2;
        bool x = query(mid, sy);

        if (x) {
            amax(rightmost, mid);
            l = mid + 1;
        }
        else {
            r = mid - 1;
        }
    }

    l = sy, r = sy;

    for (ll curr = 1; curr <= n; curr *= 2) {
        if (sy - curr < 1) {
            l = 1;
            break;
        }

        bool x = query(sx, sy - curr);
        if (!x) {
            l = sy - curr;
            break;
        }

        r = sy - curr;
    }

    while (l <= r) {
        ll mid = (l + r) / 2;
        bool x = query(sx, mid);

        if (x) {
            amin(bottommost, mid);
            r = mid - 1;
        }
        else {
            l = mid + 1;
        }
    }

    ll m = rightmost - leftmost + 1;

    ll sqleft, sqright, sqtop, sqbottom;
    ll osx = sx, osy = sy;

    sx = leftmost, sy = osy;
    while (true) {
        if (sx < 1 or sx > n or sy < 1 or sy > n) break;

        bool x = query(sx, sy);

        if (!x) {
            break;
        }

        sqleft = sx;
        sx -= (2 * m);
    }

    sx = rightmost, sy = osy;
    while (true) {
        if (sx < 1 or sx > n or sy < 1 or sy > n) break;

        bool x = query(sx, sy);

        if (!x) {
            break;
        }

        sqright = sx;
        sx += (2 * m);
    }

    sx = osx, sy = bottommost;
    while (true) {
        if (sx < 1 or sx > n or sy < 1 or sy > n) break;

        bool x = query(sx, sy);

        if (!x) {
            break;
        }

        sqbottom = sy;
        sy -= (2 * m);
    }

    sx = osx, sy = bottommost + m - 1;
    while (true) {
        if (sx < 1 or sx > n or sy < 1 or sy > n) break;

        bool x = query(sx, sy);

        if (!x) {
            break;
        }

        sqtop = sy;
        sy += (2 * m);
    }

    ll mx = (sqleft + sqright) / 2, my = (sqbottom + sqtop) / 2;
    cout << "solution " << mx << " " << my << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

aliens.cpp: In function 'void usaco(std::string)':
aliens.cpp:63:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aliens.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aliens.cpp: In function 'void solve(int)':
aliens.cpp:237:52: warning: 'sqbottom' may be used uninitialized in this function [-Wmaybe-uninitialized]
  237 |     ll mx = (sqleft + sqright) / 2, my = (sqbottom + sqtop) / 2;
      |                                          ~~~~~~~~~~^~~~~~~~
aliens.cpp:237:52: warning: 'sqtop' may be used uninitialized in this function [-Wmaybe-uninitialized]
aliens.cpp:237:21: warning: 'sqright' may be used uninitialized in this function [-Wmaybe-uninitialized]
  237 |     ll mx = (sqleft + sqright) / 2, my = (sqbottom + sqtop) / 2;
      |             ~~~~~~~~^~~~~~~~~~
aliens.cpp:237:21: warning: 'sqleft' may be used uninitialized in this function [-Wmaybe-uninitialized]

• 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: 10 / 10
• Subtask 10: 10 / 10