【sicily】 1135.飞越原野

#include<iostream>

using namespace std;

#include <queue>

#include <stdio.h>

int m,n,d;

char mat[101][101];

struct Node{

    int row,col,ntime,left;              //ntime表示所花费的时间，left表示剩余可飞行距离

    Node (int r,int c,int t,int l):row(r),col(c),ntime(t),left(l){}

    Node(){}

}temp;

int visited[101][101][101];

queue<Node> q;

int rowc[4] = {0,1,0,-1}, colc[4] = {1,0,-1,0};

void bfs(){

    while (!q.empty()){

        temp = q.front(); q.pop();

        

        int cur_left = temp.left;

        int cur_time = temp.ntime;



        if (temp.row == (m-1) && temp.col == (n-1)){

            printf("%d\n",cur_time); return ; }   



        for (int i=0;i<4;++i){

            int cur_row = temp.row + rowc[i];

            int cur_col = temp.col + colc[i];

            

            if (cur_row<0 || cur_row>m-1 || cur_col<0 || cur_col>n-1) continue;



            if (mat[cur_row][cur_col] == 'L') {}

            else{

                if(!visited[cur_row][cur_col][cur_left]){

                    q.push(Node(cur_row, cur_col, cur_time+1, cur_left));

                    visited[cur_row][cur_col][cur_left] = 1;

                }

            }



            for (int j=2;j<=cur_left;++j){

                int fly_row = temp.row + rowc[i]*j;

                int fly_col = temp.col + colc[i]*j;



                if (fly_row<0 || fly_row>m-1 || fly_col<0 || fly_col>n-1) break;

                if (mat[fly_row][fly_col] == 'L') continue;



                if (!visited[fly_row][fly_col][cur_left-j]){

                    q.push( Node(fly_row, fly_col, cur_time+1, cur_left-j));

                    visited[fly_row][fly_col][cur_left-j] = 1;

                }

            }

        }

    }

    cout<<"impossible\n";

}

int main(){

    scanf("%d%d%d",&m,&n,&d);

    for (int i=0;i<m;++i){

        for (int j=0;j<n;++j){

            cin>>mat[i][j];

            for (int k=0;k<=d;++k) visited[i][j][k] = 0;

        }

    }

    q.push(Node(0,0,0,d));

    visited[0][0][d] = 1;

    bfs();

    return 0;

}