#include<bits/stdc++.h>
using namespace std;
#define int long long
int examine(int X, int Y) {
cout << "examine " << X << ' ' << Y << endl;
string s;
cin >> s;
return s == "true";
}
void solution(int x, int y) {
cout << "solution " << x << ' ' << y << endl;
return;
}
// TODO: global variables can be declared here
int n;
int yes(int x,int y){
if(min(x,y)<=0||max(x,y)>n)return false;
return examine(x,y);
}
pair<int,int>border(int dx,int dy,int x0,int y0){
int step=1;
int x=x0,y=y0;
while(yes(x0+step*dx,y0+step*dy))step*=2;
int lx=x0+step/2*dx,rx=x0+step*dx;
int ly=y0+step/2*dy,ry=y0+step*dy;
while(!(lx==rx&&ly==ry)){
int mx=(lx+rx+dx)/2;
int my=(ly+ry+dy)/2;
if(yes(mx,my)){
lx=mx;ly=my;
}
else{
rx=mx-dx;ry=my-dy;
}
}
return make_pair(lx,ly);
}
void findCenter(int N, int X0, int Y0) {
// TODO: implementation
n=N;
int l=border(-1,0,X0,Y0).first;
int r=border(1,0,X0,Y0).first;
int d=border(0,-1,X0,Y0).second;
int m=r-l+1;
int mx=l+m/2;
int my=d+m/2;
m*=2;
if(yes(mx+m,my)&&!yes(mx-m,my)){
if(yes(mx+m*2,my))mx+=m;
else mx+=m/2,my+=m/2;
}
else if(!yes(mx+m,my)&&yes(mx-m,my)){
if(yes(mx-m*2,my))mx-=m;
else mx-=m/2,my+=m/2;
}
if(!yes(mx,my-m))my+=m;
if(!yes(mx,my+m))my-=m;
solution(mx,my);
return;
}
Compilation message
aliens.cpp: In function 'std::pair<long long int, long long int> border(long long int, long long int, long long int, long long int)':
aliens.cpp:24:9: warning: unused variable 'x' [-Wunused-variable]
24 | int x=x0,y=y0;
| ^
aliens.cpp:24:14: warning: unused variable 'y' [-Wunused-variable]
24 | int x=x0,y=y0;
| ^
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/crt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status
