Submission #45520

#	Time	Username	Problem	Language	Result	Execution time	Memory
45520		reality	Snake Escaping (JOI18_snake_escaping)	C++17	100 / 100	991 ms	65536 KiB

snake_escaping

#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
int D0[1 << 20];
int D1[1 << 20];
char str[1 << 20];
int coef[1 << 20];
char s[64];
int main(void)
{
    int n,q;
    scanf("%d%d%s",&n,&q,str);
    const int N = 1 << n;
    for (int i = 0;i < N;++i)
    	str[i] -= '0';
    for (int i = 0;i < N;++i)
    	coef[i] = __builtin_popcount(i) & 1 ? -1 : 1;
    for (int i = 0;i < N;++i)
    	D0[i] = D1[i] = str[i];
    for (int i = 0;i < n;++i)
    	for (int mask = 0;mask < N;++mask)
    		if ((mask >> i) & 1)
    			D0[mask ^ (1 << i)] += D0[mask];
    		else
    			D1[mask ^ (1 << i)] += D1[mask];
   	while (q --) {
    	scanf("%s",s);
    	reverse(s,s + n);
    	int a = 0,b = 0,c = 0;
    	int la = 0,lb = 0,lc = 0;
    	for (int i = 0;i < n;++i) {
    		if (s[i] == '0')
    			a |= 1 << i,++la;
    		else
    		if (s[i] == '1')
    			b |= 1 << i,++lb;
    		else
    			c |= 1 << i,++lc;
    	}
    	int ans = 0;
    	if (la <= lb && la <= lc) {
    		for (int mask = a;mask >= 0;mask = !mask ? -1 : ((mask - 1) & a))
    			ans += coef[mask] * D0[(N - 1) ^ mask ^ c];
    	} else
    	if (lb <= la && lb <= lc) {
    		for (int mask = b;mask >= 0;mask = !mask ? -1 : ((mask - 1) & b))
    			ans += coef[mask] * D1[mask ^ c];
    	} else {
    		for (int mask = c;mask >= 0;mask = !mask ? -1 : ((mask - 1) & c))
    			ans += str[mask ^ b];
    	}
    	ans = abs(ans);
    	printf("%d\n",ans);
    }
    return 0;
}

Compilation message (stderr)

snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:32:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for (int i = 0;i < n;++i)
     ^~~
snake_escaping.cpp:38:5: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
     while (q --) {
     ^~~~~
snake_escaping.cpp:24:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%s",&n,&q,str);
     ~~~~~^~~~~~~~~~~~~~~~~~~~
snake_escaping.cpp:39:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
      scanf("%s",s);
      ~~~~~^~~~~~~~

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