Submission #548273

#	Time	Username	Problem	Language	Result	Execution time	Memory
548273		MilosMilutinovic	Snake Escaping (JOI18_snake_escaping)	C++14	22 / 100	670 ms	32668 KiB

snake_escaping

#include <bits/stdc++.h>
using namespace std;
const int N=(1<<20)+5;
const int M=1600050;
int l,n,q,lst[M],pw[20],ans[N],dp[M];
char s[N],qs[25];
void calc(){
	pw[0]=1;
	for(int i=1;i<14;i++)pw[i]=pw[i-1]*3;
	for(int i=0;i<M;i++){
		vector<int> bits;
		int x=i;
		while(x>0)bits.push_back(x%3),x/=3;
		lst[i]=-1;
		for(int j=0;j<bits.size();j++)if(bits[j]==2)lst[i]=j;
	}
}
void BruteForce(){
	memset(dp,0,sizeof *dp);
	for(int i=0;i<n;i++){
		int sum=0,x=i,b=0;
		while(x>0)sum+=(x%2)*pw[b++],x/=2;
		dp[sum]+=(int)(s[i]-'0');
	}
	for(int i=0;i<M;i++)if(lst[i]!=-1){
		dp[i]+=dp[i-2*pw[lst[i]]];
		dp[i]+=dp[i-pw[lst[i]]];
	}
	while(q--){
		scanf("%s",qs);
		int sum=0;
		for(int i=0;i<l;i++)sum+=(qs[i]=='0'?0:(qs[i]=='1'?1:2))*pw[l-i-1];
		printf("%i\n",dp[sum]);
	}
}
int main(){
	scanf("%i%i",&l,&q);
	scanf("%s",s);
	n=(1<<l),calc();
	if(l<=13){
		BruteForce();
		return 0;
	}
	return 0;
}

Compilation message (stderr)

snake_escaping.cpp: In function 'void calc()':
snake_escaping.cpp:15:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |   for(int j=0;j<bits.size();j++)if(bits[j]==2)lst[i]=j;
      |               ~^~~~~~~~~~~~
snake_escaping.cpp: In function 'void BruteForce()':
snake_escaping.cpp:30:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |   scanf("%s",qs);
      |   ~~~~~^~~~~~~~~
snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:37:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |  scanf("%i%i",&l,&q);
      |  ~~~~~^~~~~~~~~~~~~~
snake_escaping.cpp:38:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |  scanf("%s",s);
      |  ~~~~~^~~~~~~~

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