Submission #101827

#	Time	Username	Problem	Language	Result	Execution time	Memory
101827		KCSC	Snake Escaping (JOI18_snake_escaping)	C++14	100 / 100	1161 ms	43076 KiB

snake_escaping

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

const int DIM = 20;

char str[1 << DIM], aux[DIM];
int udp[1 << DIM], ddp[1 << DIM], cbit[1 << DIM];

int main(void) {
#ifdef HOME
	freopen("snake.in", "r", stdin);
	freopen("snake.out", "w", stdout);
#endif
	int n, q; scanf("%d %d\n%s\n", &n, &q, str);
	for (int msk = 0; msk < (1 << n); ++msk) {
		cbit[msk] = cbit[msk >> 1] + (msk & 1);
		udp[msk] = ddp[msk] = str[msk] - '0'; }
	for (int b = 0; b < n; ++b) {
		for (int msk = 0; msk < (1 << n); ++msk) {
			if (msk & (1 << b)) {
				udp[msk ^ (1 << b)] += udp[msk]; }
			else {
				ddp[msk ^ (1 << b)] += ddp[msk]; } } }
	while (q--) {
		int msk0 = 0, msk1 = 0, mskq = 0; 
		scanf("%s\n", aux); reverse(aux, aux + n);
		for (int i = 0; i < n; ++i) {
			if (aux[i] == '0') { msk0 ^= (1 << i); } 
			if (aux[i] == '1') { msk1 ^= (1 << i); }
			if (aux[i] == '?') { mskq ^= (1 << i); } }
		int ans = 0;
		if (cbit[mskq] <= 7) {
			for (int axm = mskq, nr = (1 << cbit[mskq]); nr; (--axm) &= mskq, --nr) {
				ans += str[axm ^ msk1] - '0'; } }
		else if (cbit[msk0] <= 7) {
			for (int axm = msk0, nr = (1 << cbit[msk0]); nr; (--axm) &= msk0, --nr) {
				ans += udp[msk1 ^ axm] * ((cbit[axm] & 1) ? -1 : 1); } }
		else if (cbit[msk1] <= 7) {
			for (int axm = msk1, nr = (1 << cbit[msk1]); nr; (--axm) &= msk1, --nr) {
				ans += ddp[mskq ^ msk1 ^ axm] * ((cbit[axm] & 1) ? -1 : 1); } }
		printf("%d\n", ans); }		   
	return 0; }

Compilation message (stderr)

snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:14:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int n, q; scanf("%d %d\n%s\n", &n, &q, str);
            ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
snake_escaping.cpp:26:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s\n", aux); reverse(aux, aux + n);
   ~~~~~^~~~~~~~~~~~~

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