IcyFloor

#include<bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
using pipii=pair<int,pii>;
int dis[1010][1010];
bool visited[1010][1010];
pii walk[4]={{0,1},{1,0},{0,-1},{-1,0}};//R,D,L,U;
int main(){
    int n;
    scanf("%d",&n);
    bool a[n][n];
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            scanf("%d",&a[i][j]);
            dis[i][j]=2e9;
        }
    }
    dis[0][0]=0;
    priority_queue<pipii,vector<pipii>,greater<pipii>> Q;
    Q.push({0,{0,0}});
    while(!Q.empty()){
        int d=Q.top().first;
        int x=Q.top().second.first;
        int y=Q.top().second.second;
        Q.pop();
        if(x==n-1&&y==n-1){
            printf("%d",d);
            return 0;
        }
        if(visited[x][y]) continue;
        visited[x][y]=true;
        for(int i=0;i<4;i++){
            int nd=d;
            int nx=x;
            int ny=y;
            while(true){
                nx+=walk[i].first;
                ny+=walk[i].second;
                nd++;
                if(nx<0||ny<0||nx==n||ny==n||a[nx][ny]==1){
                    ny-=walk[i].second;
                    nx-=walk[i].first;
                    nd-=1;
                    if(nd<dis[nx][ny]&&!visited[nx][ny]){
                        dis[nx][ny]=nd;
                        Q.push({nd,{nx,ny}});
                    }
                    break;
                }
            }
        }
    }
}