Submission #584527

#	Time	Username	Problem	Language	Result	Execution time	Memory
584527		Dan4Life	Aliens (IOI07_aliens)	C++17	0 / 100	3079 ms	296 KiB

aliens

#include <bits/stdc++.h>
using namespace std;
int n, m, l, r, u, d, X, Y, bx, by;
map<pair<int,int>,bool> M;

bool query(int x, int y){
    if(x<1 or y<1 or x>n or y>n) return 0;
    if(M.count({x,y})) return M[{x,y}];
    cout << "examine " << x << " " << y << endl;
    string s; cin >> s; return M[{x,y}]=(s=="true");
}

int binsearch(int x, int y, int dx, int dy){
    int l = 0, r = n;
    while(l<r){
        int mid = (l+r)/2;
        int x = query(x+dx*mid,y+dy*mid);
        if(x) l=mid; else r=mid-1;
    }
    return (dx==0?y+dy*l:x+dx*l);
}

bool chk(int m){
    int x = r, y = Y, cnt = 1;
    while(query(x+m, y+m)) x+=m, y+=m;
    while(query(x+2*m, y)) x+=2*m;
    while(query(x-2*m, by)) x-=2*m, cnt++;     
    return cnt==3;
}

int32_t main()
{
    cin >> n >> X >> Y; M[{X,Y}]=1;
    l = binsearch(X,Y,-1,0);
    r = binsearch(X,Y,1,0);
    d = binsearch(X,Y,0,-1);
    int m1 = r-l+1;
    if(chk(m1)) m = m1;
    if(m1%3 and chk(m1/3)) m = m1/3;
    if(m1%5 and chk(m1/5)) m = m1/5;
    
    u = m-d-1;
    int bx = X-l, by = Y-d;
    while(query(bx-m, by-m)) bx-=m, by-=m;
    while(query(bx, by-2*m)) by-=2*m;
    while(query(bx-2*m, by)) bx-=2*m;
    int ansx = bx+m*2+m/2, ansy = by+m*2+m/2; 
    cout << "solution " << ansx << " " << ansy << endl;
}

Compilation message (stderr)

aliens.cpp: In function 'int binsearch(int, int, int, int)':
aliens.cpp:17:22: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   17 |         int x = query(x+dx*mid,y+dy*mid);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~

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