Submission #260155

#	Time	Username	Problem	Language	Result	Execution time	Memory
260155		jdh	Awesome Arrowland Adventure (eJOI19_adventure)	C++17	100 / 100	113 ms	17400 KiB

adventure

#include <bits/stdc++.h>
using namespace std;
map<char,int> mp = { {'N',0},{'E',1},{'S',2},{'W',3} };
vector<tuple<int,int,char>> dirs = { {-1,0,'N'},{0,1,'E'},{1,0,'S'},{0,-1,'W'} };
int main(){
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n,m;
  cin >> n >> m;
  vector<string> vs(n);
  for(int i = 0; i < n; ++i) cin >> vs[i];
  if(vs[0][0] == 'X'){
    cout << -1;
    return 0;
  }
  vector<vector<int>> val(n,vector<int>(m,-1));
  set<tuple<int,int,int>> sp;
  sp.emplace(0,0,0);
  while(!sp.empty()){
    int a,x,y;
    tie(a,x,y) = *begin(sp);
    sp.erase(begin(sp));
    if(val[x][y] >= 0) continue;
    val[x][y] = a;
    if(x == n-1 and y == m-1) break;
    for(auto& dir : dirs){
      int dx,dy;
      char d;
      tie(dx,dy,d) = dir;
      int x1 = x+dx,y1 = y+dy;
      if(0 <= x1 and x1 < n and 0 <= y1 and y1 < m){
        if(val[x1][y1] == -1){
          if(vs[x1][y1] != 'X' or (x1 == n-1 and y1 == m-1)){
            int delta = (mp[d]+4-mp[vs[x][y]])%4;
            sp.emplace(a+delta,x1,y1);
          }
        }
      }
    }
  }
  cout << val[n-1][m-1];
  return 0;
}

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