Submission #705393

#	Time	Username	Problem	Language	Result	Execution time	Memory
705393		089487	Snake Escaping (JOI18_snake_escaping)	C++14	22 / 100	2011 ms	20000 KiB

snake_escaping

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include<bits/stdc++.h>
#define quick ios::sync_with_stdio(0);cin.tie(0);
#define rep(x,a,b) for(int x=a;x<=b;x++)
#define repd(x,a,b) for(int x=a;x>=b;x--)
#define lowbit(x) (x&-x)
#define sz(x) (int)(x.size())
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define mp make_pair
#define eb emplace_back
using namespace std;
typedef complex<int> P;
#define X real()
#define Y imag()
typedef pair<int,int> pii;
void debug(){
    cout<<"\n";
}
template <class T,class ... U >
void debug(T a, U ... b){
    cout<<a<<" ",debug(b...);
}
const int M=20;
const int N=(1<<M)+7;
const int INF=1e18;
int dp1[N];
int dp2[N];
int a[N];
int now=0;
int ans=0;
string s;
void dfs(int x,int n){
	if(x>=n){
		ans+=a[now];
		return ;
	}
	if(s[x]=='0'||s[x]=='?'){
		dfs(x+1,n);
	}
	if(s[x]=='1'||s[x]=='?'){
		now+=(1<<x);
		dfs(x+1,n);
		now-=(1<<x);
	}
}
int change=0;
void dfs2(int x,int n){
	if(x>=n){
		if(change) ans-=dp1[now];
		else ans+=dp1[now];
		return ;
	}
	if(s[x]=='1'){
		now+=(1<<x);
		dfs2(x+1,n);
		now-=(1<<x);
		change^=1;
		dfs2(x+1,n);
		change^=1;
	}
	else if(s[x]=='?'){
		now+=(1<<x);
		dfs2(x+1,n);
		now-=(1<<x);
	}
	else{
		dfs2(x+1,n);
	}
}

void dfs3(int x,int n){
	if(x>=n){
		if(change) ans-=dp2[now];
		else ans+=dp2[now];
		return ;
	}
	if(s[x]=='0'){
		change^=1;
		now+=(1<<x);
		dfs3(x+1,n);
		change^=1;
		now-=(1<<x);
		dfs3(x+1,n);
	}
	else if(s[x]=='?'){
		dfs3(x+1,n);
	}
	else{
		now+=(1<<x);
		dfs3(x+1,n);
		now-=(1<<x);
	}
}

signed main(){
	quick
	int n,q;
	cin>>n>>q;
	string S;
	cin>>S;
	rep(i,0,(1<<n)-1){
		dp1[i]=dp2[i]=a[i]=S[i]-'0';
	}
	rep(i,0,n-1){
		rep(mask,0,(1<<n)-1){
			if(mask&(1<<i)){
				dp1[mask]+=dp1[mask^(1<<i)];
			}
			else dp2[mask]+=dp2[mask^(1<<i)];
		}
	}
	while(q--){
		cin>>s;
		reverse(all(s));
		int a,b,c;
		for(char _c:s){
			if(_c=='?') a++;
			else if(_c=='1') b++;
			else c++;
		}
		ans=change=now=0;
		if(a<=min(b,c)){
			dfs(0,n);
		}
		else if(b<=min(a,c)){
			dfs2(0,n);
		}
		else{
			dfs3(0,n);
		}
		cout<<ans<<"\n";
	}

	return 0;
}

Compilation message (stderr)

snake_escaping.cpp:28:15: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   28 | const int INF=1e18;
      |               ^~~~
snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:118:11: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  118 |   int a,b,c;
      |           ^
snake_escaping.cpp:118:9: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  118 |   int a,b,c;
      |         ^
snake_escaping.cpp:118:7: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  118 |   int a,b,c;
      |       ^

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 10 / 10
• Subtask 4: 0 / 53
• Subtask 5: 0 / 25