Language: C++

v#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <cstring>
#include <climits>
#include <string.h>
#include <stdio.h>
#define LL long long
#define all(x) (x).begin(),(x).end()
#define pii pair<int,int>
#define piii pair<int, pii >
#define REP(i,n) for (int (i)=0;(i)<(n);(i)++)
#define vi vector<int>
#define vpi vector< pii >
#define INF 2147483647
#define big 19260817
#define pb push_back
#define mp make_pair
using namespace std;
const int Maxk=1005;
string mul(string a,string b){
	int res[Maxk];
	memset(res,0,sizeof(res));
	reverse(a.begin(),a.end());
	reverse(b.begin(),b.end());
	for (int i=0;i<a.length();i++){
		for (int j=0;j<b.length();j++){
			res[i+j]+=(a[i]-'0')*(b[j]-'0');
		}
	}
	for (int i=0;i<Maxk;i++){
		if (res[i]>=10) {
			res[i+1]+=(res[i]/10);
			res[i]%=10;
		}
	}
	string ret;
	bool flag=false;
	for (int i=Maxk-1;i>=0;i--){
		if (flag || res[i]){
			flag=true;
			ret=ret+(char)(res[i]+'0');
		}
	}
	if (ret=="") ret="0";
	return ret;
}
string add(string a,string b){
	if (a.length()<b.length()) swap(a,b);
	while (a.length()!=b.length()){
		b='0'+b;
	}
	for (int i=a.length()-1;i>=0;i--){
		a[i]+=(b[i]-'0');
		if (a[i]>'9' && i){
			a[i]-=10;
			a[i-1]++;
		}
	}
	if (a[0]>'9'){
		a[0]-=10;
		a='1'+a;
	}
	return a;
}
// cf IO: I64d
// atcoder IO: ｌｌｄ
const int Maxn=4005;
char ans[Maxn];
char ask(int x,int y){
	printf("? %d %d\n",x,y);
	fflush(stdout);
	char c;
	scanf("\n%c",&c);
	return c;
}
vector<int> now;
int main(){
	int a,b;
	scanf("%d %d",&a,&b);
	if (b>=a){
		printf("Impossible\n");
		fflush(stdout);
		return 0;
	}
	now.push_back(0);
	for (int i=1;i<a+b;i++){
		if (now.empty()){
			now.push_back(i);
			continue;
		}
		int x=now.back();
		char c=ask(x,i);
		if (c=='N'){
			now.pop_back();
			//cerr<<123<<endl;
		}
		else{
			now.push_back(i);
		}
	}
	int t=now.back();
	for (int i=0;i<a+b;i++){
		char c=ask(t,i);
		if (c=='N') ans[i]='0'; else ans[i]='1';
	}
	ans[a+b]='\0';
	printf("! %s\n",ans);
	fflush(stdout);
	return 0;
}


Compiler output:
a.cc:1:2: error: stray '#' in program
    1 | v#include <iostream>
      |  ^
a.cc:1:1: error: 'v' does not name a type; did you mean 'vi'?
    1 | v#include <iostream>
      | ^
      | vi
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/istream:40,
                 from /usr/include/c++/14/sstream:40,
                 from a.cc:2:
/usr/include/c++/14/bits/postypes.h:68:11: error: 'ptrdiff_t' does not name a type
   68 |   typedef ptrdiff_t     streamsize; // Signed integral type
      |           ^~~~~~~~~
/usr/include/c++/14/bits/postypes.h:41:1: note: 'ptrdiff_t' is defined in header '<cstddef>'; this is probably fixable by adding '#include <cstddef>'
   40 | #include <cwchar> // For mbstate_t
  +++ |+#include <cstddef>
   41 | 
In file included from /usr/include/c++/14/bits/exception_ptr.h:38,
                 from /usr/include/c++/14/exception:166,
                 from /usr/include/c++/14/ios:41:
/usr/include/c++/14/new:131:26: error: declaration of 'operator new' as non-function
  131 | _GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                          ^~~~~~~~
/usr/include/c++/14/new:131:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  131 | _GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                                            ^~~~~~
In file included from /usr/include/wchar.h:35,
                 from /usr/include/c++/14/cwchar:44,
                 from /usr/include/c++/14/bits/postypes.h:40:
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:132:41: error: attributes after parenthesized initializer ignored [-fpermissive]
  132 |   __attribute__((__externally_visible__));
      |                                         ^
/usr/include/c++/14/new:133:26: error: declaration of 'operator new []' as non-function
  133 | _GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                          ^~~~~~~~
/usr/include/c++/14/new:133:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  133 | _GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:134:41: error: attributes after parenthesized initializer ignored [-fpermissive]
  134 |   __attribute__((__externally_visible__));
      |                                         ^
/usr/include/c++/14/new:140:29: error: 'std::size_t' has not been declared
  140 | void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
      |                             ^~~
/usr/include/c++/14/new:142:31: error: 'std::size_t' has not been declared
  142 | void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
      |                               ^~~
/usr/include/c++/14/new:145:26: error: declaration of 'operator new' as non-function
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                          ^~~~~~~~
/usr/include/c++/14/new:145:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:145:52: error: expected primary-expression before 'const'
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                                    ^~~~~
/usr/include/c++/14/new:147:26: error: declaration of 'operator new []' as non-function
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                          ^~~~~~~~
/usr/include/c++/14/new:147:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:147:54: error: expected primary-expression before 'const'
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                                      ^~~~~
/usr/include/c++/14/new:154:26: error: declaration of 'operator new' as non-function
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                          ^~~~~~~~
/usr/include/c++/14/new:154:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:154:68: error: expected primary-expression before ')' token
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                                                                    ^
/usr/include/c++/14/new:155:73: error: attributes after parenthesized initializer ignored [-fpermissive]
  155 |   __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
      |                                                                         ^
/usr/include/c++/14/new:156:26: error: declaration of 'operator new' as non-function
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                          ^~~~~~~~
/usr/include/c++/14/new:156:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:156:68: error: expected primary-expression before ',' token
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                    ^
/usr/include/c++/14/new:156:70: error: expected primary-expression before 'const'
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                      ^~~~~
/usr/include/c++/14/new:162:26: error: declaration of 'operator new []' as non-function
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                          ^~~~~~~~
/usr/include/c++/14/new:162:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:162:70: error: expected primary-expression before ')' token
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                                                                      ^
/usr/include/c++/14/new:163:73: error: attributes after parenthesized initializer ignored [-fpermissive]
  163 |   __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
      |                                                                         ^
/usr/include/c++/14/new:164:26: error: declaration of 'operator new []' as non-function
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                          ^~~~~~~~
/usr/include/c++/14/new:164:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:164:70: error: expected primary-expression before ',' token
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                      ^
/usr/include/c++/14/new:164:72: error: expected primary-expression before 'const'
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                        ^~~~~
/usr/include/c++/14/new:171:29: error: 'std::size_t' has not been declared
  171 | void operator delete(void*, std::size_t, std::align_val_t)
      |                             ^~~
/usr/include/c++/14/new:173:31: error: 'std::size_t' has not been declared
  173 | void operator delete[](void*, std::size_t, std::align_val_t)
      |                               ^~~
/usr/include/c++/14/new:179:33: error: declaration of 'operator new' as non-function
  179 | _GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
      |                                 ^~~~~~~~
/usr/include/c+