Submission #64588

#	Time	Username	Problem	Language	Result	Execution time	Memory
64588		keko37	Snake Escaping (JOI18_snake_escaping)	C++14	75 / 100	1971 ms	66560 KiB

snake_escaping

#include<iostream>

using namespace std;

const int MAXN = (1<<20) + 10;

int n, q, a, b, c, sol, mask, N, rev, count, i, j, tc;
char l[30], cc;
int val[MAXN], sum0[MAXN], sum1[MAXN], pc[MAXN];

void precompute () {
	for (i=0; i<(1<<n); i++) {
		pc[i] = pc[i - (i&-i)]+1;
		sum0[i] = val[i];
		sum1[i] = val[i ^ ((1<<n) - 1)];
	}
	for (i=0; i<n; i++) {
		for (j=0; j<(1<<n); j++) {
			if (j & (1<<i)) sum0[j] += sum0[j ^ (1<<i)];
			if (j & (1<<i)) sum1[j] += sum1[j ^ (1<<i)];
		}
	}
}
  #define pcc(x) putchar(x);
    
int main () {
	cin >> n >> q;
	do {
		cc = getchar();
	} while (!(cc>='0' && cc<='9'));
	for (i=0; i<(1<<n); i++) {
		if (i>0) {
			cc = getchar();
		}
		val[i] = cc - '0';
	}
	precompute();
	for (tc=0; tc<q; tc++) {
		a = b = c = 0;
		do {
			cc = getchar();
		} while (!(cc=='0' || cc=='1' || cc=='?'));
		for (i=0; i<n; i++) {
			if (i>0) cc = getchar();
			l[i] = cc;
			if (l[i] == '?') {
				a ^= (1<<(n-1-i));
			} else if (l[i] == '0') {
				b ^= (1<<(n-1-i));
			} else {
				c ^= (1<<(n-1-i));
			}
		}
		sol = 0, mask = 0;
		if (pc[a] <= pc[b] && pc[a] <= pc[c]) {
			for (mask = a; ; mask = (mask - 1) & a) {
				sol += val[mask | c];
				if (!mask) break;
			}
		} else if (pc[b] <= pc[a] && pc[b] <= pc[c]) {
			for (mask = b; ; mask = (mask-1) & b) {
				rev = mask | a;
				if (pc[rev] & 1) {
					sol -= sum1[rev];
				} else {
					sol += sum1[rev];
				}
				if (!mask) break;
			}
			if (sol < 0) sol = -sol;
		} else {
			for (mask = c; ; mask = (mask - 1) & c) {
				rev = mask | a;
				if (pc[rev] & 1) {
					sol -= sum0[rev];
				} else {
					sol += sum0[rev];
				}
				if (!mask) break;
			}
			if (sol < 0) sol = -sol;
		}

        N = sol, rev, count = 0;
        rev = N;
        if (N == 0) { pcc('0'); putchar('\n'); continue ;}
        while ((rev % 10) == 0) { count++; rev /= 10;} //obtain the count of the number of 0s
        rev = 0;
        while (N != 0) { rev = (rev<<3) + (rev<<1) + N % 10; N /= 10;}  //store reverse of N in rev
        while (rev != 0) { pcc(rev % 10 + '0'); rev /= 10;}
        while (count--) pcc('0');
		putchar('\n');
	}
	return 0;
}

Compilation message (stderr)

snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:84:31: warning: right operand of comma operator has no effect [-Wunused-value]
         N = sol, rev, count = 0;
                               ^

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