Submission #1095454

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095454		MateiKing80	Nautilus (BOI19_nautilus)	C++17	100 / 100	176 ms	1372 KiB

nautilus

#include <bits/stdc++.h>

using namespace std;

int r, c, m;
vector<string> grid;
bool valid_pos(int i, int j)
{
    return !(i < 0 || j < 0 || i >= r || j >= c || grid[i][j] == '#');
}

int main()
{
    cin >> r >> c >> m;
    grid.resize(r);
    for(int i = 0; i < r; i ++)
        cin >> grid[i];
    string msg;
    cin >> msg;
    bitset<1000> reach[r], tmp[r], sea[r];
    for(int i = 0; i < r; i ++)
        for(int j = 0; j < c; j ++)
        {
            sea[i][j] = grid[i][c-1-j] == '.';
            reach[i][j] = grid[i][c-1-j] == '.';
        }
    for(char w : msg)
    {
        for(int i = 0; i < r; i ++)
        {
            if(w == 'W')
                reach[i] = (reach[i]<<1)&sea[i];
            if(w == 'E')
                reach[i] = (reach[i]>>1)&sea[i];
            if(w == 'N')
                if(i+1 < r)
                    reach[i] = reach[i+1] & sea[i];
                else
                    reach[i].reset();
            if(w == '?')
            {
                tmp[i] = (reach[i]<<1)|(reach[i]>>1);
                if(i)
                    tmp[i] |= reach[i-1];
                if(i+1 < r)
                    tmp[i] |= reach[i+1];
                tmp[i] &= sea[i];
            }
        }
        for(int i = r-1; i >= 0; i --)
            if(w == 'S')
                if(i)
                    reach[i] = reach[i-1] & sea[i];
                else
                    reach[i].reset();
        for(int i = 0; i < r; i ++)
            if(w == '?')
                reach[i] = tmp[i];
    }
    int ans = 0;
    for(int i = 0; i < r; i ++)
        ans += reach[i].count();
    cout << ans << '\n';
}

Compilation message (stderr)

nautilus.cpp: In function 'int main()':
nautilus.cpp:35:15: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   35 |             if(w == 'N')
      |               ^
nautilus.cpp:51:15: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   51 |             if(w == 'S')
      |               ^

• Subtask 1: 29 / 29
• Subtask 2: 37 / 37
• Subtask 3: 34 / 34