Dijkstra2D

#include <bits/stdc++.h>
#define PI 3.14159265358979323846
#define mod 998244353
#define INF 999999999
#define MAX 110
#define f first
#define s second
#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define vi vector<int>
#define vii vector< pair<int,int> >
#define sws ios_base::sync_with_stdio(false)
#define forn(i, n) for(int i=0; i<(int)(n); i++)
#define endl '\n'

using namespace std;

// https://neps.academy/lesson/215

typedef struct
{
    int dist;
    int x, y;
} vertice;

struct Comp
{
    bool operator()(vertice& a, vertice& b)
    {
        return a.dist > b.dist;
    }
};

int N;
bool mat[MAX][MAX], visitado[MAX][MAX];
int distancia[MAX][MAX];

int coordx[4]={0,1,0,-1};
int coordy[4]={1,0,-1,0};

void dijkstra(int i, int j)
{
    int a, b;
    vertice aux, aux2;

    aux.dist=0;
    aux.x=i;
    aux.y=j;

    priority_queue< vertice, vector<vertice>, Comp >fila;
    fila.push(aux);

    while(!fila.empty())
    {
        aux=fila.top();
        fila.pop();
        if(!visitado[aux.x][aux.y])
        {
            visitado[aux.x][aux.y]=true;
            distancia[aux.x][aux.y]=aux.dist;

            for(int i=0;i<4;i++)
            {
                a=aux.x+coordx[i];
                b=aux.y+coordy[i];

                if(a>=0 and b>=0 and a<N and b<N and !visitado[a][b])
                {
                    aux2.x=a;aux2.y=b;
                    aux2.dist=aux.dist+mat[a][b];
                    fila.push(aux2);
                }
            }
        }
    }
}

int main()
{
    sws;
    cin >> N;

    forn(i,N)
        forn(j,N)
        {
            cin >> mat[i][j];
            visitado[i][j]=false;
            distancia[i][j]=INF;
        }

    distancia[0][0]=0;
    dijkstra(0,0);

    cout << distancia[N-1][N-1] << endl;

    return 0;
}