Submission #1036340

#	Time	Username	Problem	Language	Result	Execution time	Memory
1036340		juicy	Awesome Arrowland Adventure (eJOI19_adventure)	C++17	100 / 100	18 ms	4256 KiB

adventure

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = 505;
const int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};

int n, m;
int d[N][N];
char a[N][N];
bool vis[N][N];

bool inside(int i, int j) {
  return 1 <= i && i <= n && 1 <= j && j <= m && !vis[i][j];
}

int main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  cin >> n >> m;
  map<char, int> mp = {{'N', 0}, {'E', 1}, {'S', 2}, {'W', 3}};
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= m; ++j) {
      cin >> a[i][j];
    }
  }
  auto add = [&](int u, int i) {
    if ((u += i) >= 4) {
      u -= 4;
    }
    if (u < 0) {
      u += 4;
    }
    return u;
  };
  memset(d, 0x3f, sizeof(d));
  array<queue<array<int, 2>>, 4> q;
  q[0].push({1, 1});
  d[1][1] = 0;
  int sz = 1, it = 0;
  while (sz) {
    while (!q[it].size()) {
      it = add(it, 1);
    }
    auto [u, v] = q[it].front(); q[it].pop(); --sz;
    if (vis[u][v]) {
      continue;
    }
    vis[u][v] = 1;
    if (a[u][v] != 'X') {
      int p = mp[a[u][v]];
      for (int dr = 0; dr < 4; ++dr) {
        int x = u + dx[dr], y = v + dy[dr];
        if (inside(x, y)) {
          int w = add(dr, -p);
          d[x][y] = min(d[x][y], d[u][v] + w);
          q[add(it, w)].push({x, y}); ++sz;
        }
      }
    }
  }
  cout << (d[n][m] < 1e9 ? d[n][m] : -1);
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 16 / 16
• Subtask 5: 50 / 50