Submission #376484

#	Time	Username	Problem	Language	Result	Execution time	Memory
376484		astoria	Snake Escaping (JOI18_snake_escaping)	C++14	12 / 100	2084 ms	12908 KiB

snake_escaping

#include "bits/stdc++.h"
using namespace std;

int l,q,n;
int pw[25]; 

int fast_mod(const int input, const int ceil) {
    // apply the modulo operator only when needed
    // (i.e. when the input is greater than the ceiling)
    return input >= ceil ? input % ceil : input;
    // NB: the assumption here is that the numbers are positive
}

bool comp(int a, int b){
	vector<int> x,y;
	int cntx=0,cnty=0;
	for(int j=0; j<l; j++){
		int cr = fast_mod(a,3); a/=3;
		if(cr==2) cntx++;
	}
	for(int j=0; j<l; j++){
		int cr = fast_mod(b,3); b/=3;
		if(cr==2) cnty++;
	}
	return cntx<cnty;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
	cin>>l>>q; n=1<<l;
	string s; cin>>s;
	int tox[n];
	for(int i=0; i<n; i++) tox[i] = s[i]-'0';
	
	pw[0]=1;
	int k=1; for(int i=1; i<=l; i++){ k*=3; pw[i]=k;}
	int ans[k]; memset(ans,0,sizeof(ans));
	
	int ord[k];
	for(int i=0; i<k; i++) ord[i]=i;
		
	//sort(ord,ord+k,comp);
	
	if(l<=10) goto acn;
	
	for(int i=0; i<n; i++){
		int v = ord[i], vk=v;
		int tot = 0;
		for(int j=0; j<l; j++){
			int cr = fast_mod(v,3); v/=3;
			tot += ((1<<j)*cr);
		}
		ans[vk] = tox[tot];
	}
		
	for(int ahc=n; ahc<k; ahc++){
		int v = ord[ahc], tk = ord[ahc], tt = ord[ahc], vk = ord[ahc];
		for(int i=0; i<l; i++){
			int cr = fast_mod(v,3); v/=3;
			if(cr==2){
				tk-=(2*pw[i]);
				tt-=(1*pw[i]);
				break;
			}
		}
		ans[vk] = ans[tk]+ans[tt];
	}
	
	acn :
	
	for(int ahc=0; ahc<k; ahc++){
		vector<int> v; int cr=ahc;
		for(int j=0; j<l; j++){
			v.push_back(cr%3); cr/=3;
		}
		for(int i=0; i<n; i++){
			bitset<13> b(i); bool f=1;
			for(int j=0; j<l; j++){
				if(v[j]!=2 && (b[j]!=v[j])){ f=0; break;}
			}
			if(f) ans[ahc] += tox[i];
		}
	}
		
	for(int ahc=0; ahc<q; ahc++){
		string s; cin>>s;
		int qr=0;
		for(int i=0; i<l; i++){
			int pwer = l-i-1;
			if(s[i]=='1') qr += (pw[pwer]);
			if(s[i]=='?') qr += (2*pw[pwer]);
		}
		cout<<ans[qr]<<"\n";
	}
}

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