Submission #464418

#	Time	Username	Problem	Language	Result	Execution time	Memory
464418		Tenis0206	Awesome Arrowland Adventure (eJOI19_adventure)	C++11	100 / 100	68 ms	5920 KiB

adventure

#include <bits/stdc++.h>

using namespace std;
const int oo = INT_MAX;
int dx[] = {0,0,1,0,-1};
int dy[] = {0,1,0,-1,0};
int n,m,c[505][505];
priority_queue<pair<int,pair<int,int>>,vector<pair<int,pair<int,int>>>, greater<pair<int,pair<int,int>>>> h;
bool sel[505][505];
int d[505][505];
void Dijkstra(int x, int y)
{
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=m; j++)
        {
            d[i][j] = oo;
        }
    }
    d[1][1] = 0;
    if(c[x][y])
    {
        h.push({0,{x,y}});
    }
    int cnt = 0;
    while(!h.empty())
    {
        while(!h.empty() && sel[h.top().second.first][h.top().second.second])
        {
            h.pop();
        }
        if(h.empty())
        {
            break;
        }
        int k = h.top().first;
        int x = h.top().second.first;
        int y = h.top().second.second;
        h.pop();
        sel[x][y] = true;
        for(int p=1; p<=4; p++)
        {
            int xx = x + dx[p];
            int yy = y + dy[p];
            if(xx==1 && yy==1)
            {
                continue;
            }
            if(xx<1 || yy<1 || xx>n || yy>m)
            {
                continue;
            }
            int cost = 0;
            if(p>=c[x][y])
            {
                cost = p-c[x][y];
            }
            else
            {
                cost = 4-c[x][y]+p;
            }
            if(xx==n && yy==m)
            {
                ++cnt;
            }
            if(d[x][y]+cost<=d[xx][yy])
            {
                d[xx][yy] = d[x][y]+cost;
                if(c[xx][yy])
                {
                    h.push({d[xx][yy],{xx,yy}});
                }
            }
            if(cnt==2)
            {
                return;
            }
        }
    }
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m;
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=m; j++)
        {
            char ch;
            cin>>ch;
            if(ch=='E')
            {
                c[i][j] = 1;
            }
            else if(ch=='S')
            {
                c[i][j] = 2;
            }
            else if(ch=='W')
            {
                c[i][j] = 3;
            }
            else if(ch=='N')
            {
                c[i][j] = 4;
            }
        }
    }
    Dijkstra(1,1);
    if(d[n][m]==oo)
    {
        cout<<-1<<'\n';
        return 0;
    }
    cout<<d[n][m]<<'\n';
    return 0;
}

Compilation message (stderr)

adventure.cpp: In function 'void Dijkstra(int, int)':
adventure.cpp:36:13: warning: unused variable 'k' [-Wunused-variable]
   36 |         int k = h.top().first;
      |             ^

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