Wannafly交流赛1 E 迷宫2

迷宫2

优先队列  bfs

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int  inf = 987654321;
const int sz = 505 ;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pii pair<int,int>
#define lowbit(x) x&(-x)
#define X first
#define Y second 
ll g[sz][sz];
 
int T,n,m;
struct node
{
    int x, y;
    ll cost;
    node(int _x,int _y,ll _c):x(_x),y(_y),cost(_c){}
    node(){}
    bool operator<(const node&b)const
    {
        return cost > b.cost;
    }
};
 
bool vis[sz][sz]; 
int dir[4][2] = { -1,0,1,0,0,-1,0,1 };
 
ll bfs()
{
    priority_queue <node> q ;
     CLR(vis,0); 
     f(i,1,m-1) 
     if(g[1][i]!=-1)
         q.push(node(1,i,g[1][i]));
     f(i,1,n)
         if(g[i][m]!=-1)
             q.push(node(i,m,g[i][m])); 
    while(!q.empty())
    {
         node x = q.top();q.pop();
         if(vis[x.x][x.y])continue;
         vis[x.x][x.y] =1;
         if(x.x==n || x.y ==1) return x.cost;
         f(i,0,3)
         {
             int dx = x.x +dir[i][0];
             int dy = x.y+ dir[i][1];
             if(dx<1||dx>n||dy<1||dy>m) continue;
             if(g[dx][dy]==-1)continue;
             if(vis[dx][dy])continue;
             q.push(node(dx,dy,x.cost+g[dx][dy]));
         }
    }
    return -1;
     
}


void work()
{
    cin>>T>>n>>m;
    while(T--)
    {
        f(i,1,n)f(j,1,m)cin>>g[i][j];
        f(i,1,n)f(j,1,m) 
        if(g[i][j] ==-1)   g[i][j]=0;
        else if( g[i][j] ==0)   g[i][j]=-1; 
        cout<<bfs()<<endl;
    }

    
    
}


int main()
{
    FAST_IO ;
    work();
    return 0; 
}