Submission #75225

#	Time	Username	Problem	Language	Result	Execution time	Memory
75225		bogdan10bos	Snake Escaping (JOI18_snake_escaping)	C++14	100 / 100	1476 ms	46376 KiB

snake_escaping

#include <bits/stdc++.h>

using namespace std;

//#define FILE_IO

int N, Q, ans;
int i, j, q, msk;
int cnt[3];
int val[1100005], dp[1100005], dp2[1100005];
int bts[1100005];
int B, b[25];
char s[1100005];

void bck0(int pas, int msk, int smn)
{
    if(pas >= B)
    {
        ans += smn * dp[msk];
        return;
    }

    bck0(pas + 1, msk, smn);
    bck0(pas + 1, msk ^ (1 << b[pas]), -smn);
}

void bck1(int pas, int msk, int smn)
{
    if(pas >= B)
    {
        ans += smn * dp2[msk];
        return;
    }

    bck1(pas + 1, msk, smn);
    bck1(pas + 1, msk ^ (1 << b[pas]), -smn);
}

void bckq(int pas, int msk)
{
    if(pas >= B)
    {
        ans += val[msk];
        return;
    }

    bckq(pas + 1, msk);
    bckq(pas + 1, msk ^ (1 << b[pas]));
}

int main()
{
    #ifdef FILE_IO
    freopen("1.in", "r", stdin);
    freopen("1.out", "w", stdout);
    #endif

    scanf("%d%d\n", &N, &Q);
    scanf("%s\n", s);
    for(i = 0; i < (1 << N); i++)
        val[i] = dp[i] = dp2[i] = s[i] - '0';
    for(j = 0; j < N; j++)
        for(i = (1 << N) - 1; i >= 0; i--)
            if( (i & (1 << j)) == 0 )
                dp[i] += dp[i ^ (1 << j)];
    for(j = 0; j < N; j++)
        for(i = 0; i < (1 << N); i++)
            if( (i & (1 << j)) != 0 )
                dp2[i] += dp2[i ^ (1 << j)];

    for(q = 1; q <= Q; q++)
    {
        scanf("%s\n", s);
        reverse(s, s + N);
        cnt[0] = cnt[1] = cnt[2] = 0;
        for(j = 0; j < N; j++)
        {
            if(s[j] == '0') cnt[0]++;
            else if(s[j] == '1')    cnt[1]++;
            else if(s[j] == '?')    cnt[2]++;
        }

        if(cnt[0] < cnt[1] && cnt[0] < cnt[2])
        {
            msk = 0;
            B = 0;
            for(i = 0; i < N; i++)
            {
                if(s[i] == '1') msk |= (1 << i);
                if(s[i] == '0') b[B++] = i;
            }

            ans = 0;
            bck0(0, msk, 1);
            printf("%d\n", ans);
        }
        else if(cnt[1] < cnt[2])
        {
            msk = 0;
            B = 0;
            for(i = 0; i < N; i++)
            {
                if(s[i] == '1')
                {
                    msk |= (1 << i);
                    b[B++] = i;
                }
                if(s[i] == '?')
                    msk |= (1 << i);
            }

            ans = 0;
            bck1(0, msk, 1);
            printf("%d\n", ans);
        }
        else
        {
            msk = 0;
            B = 0;
            for(i = 0; i < N; i++)
            {
                if(s[i] == '?') b[B++] = i;
                else    msk |= ((s[i] - '0') << i);
            }

            ans = 0;
            bckq(0, msk);
            printf("%d\n", ans);
        }
    }

    return 0;
}

Compilation message (stderr)

snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:58:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d\n", &N, &Q);
     ~~~~~^~~~~~~~~~~~~~~~~~
snake_escaping.cpp:59:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s\n", s);
     ~~~~~^~~~~~~~~~~
snake_escaping.cpp:73:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%s\n", s);
         ~~~~~^~~~~~~~~~~

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