codeforces 1064D 双端队列BFS

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<vector>
#include<set>
#include<bitset>
#define INF 0x3f3f3f3f
#define LL long long
using namespace std;
const int maxn=200010;
int a[maxn];
char s[2010][2010];
bool v[2010][2010];
int n,m,r,c,rr,cc;
int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
bool valid(int x,int y){
    return x>=1&&x<=n&&y>=1&&y<=m&&s[x][y]!=‘*‘;
}
struct node{
    int x,y,cnt_l,cnt_r;
};
deque<node> q;
void bfs(void){
    node tmp=(node){r,c,rr,cc};
    node tmp1;
    int ans=0;
    q.push_back(tmp);
    while(!q.empty()){
        tmp=q.front();
        q.pop_front();
        int x=tmp.x,y=tmp.y;
        if(v[x][y])continue;
        v[x][y]=1;
        ans++;
        for(int i=0;i<4;i++){
            tmp1=tmp;
            int tx=x+dx[i];
            int ty=y+dy[i];
            if(valid(tx,ty)){
                if(i==1){
                    if(tmp.cnt_r>0){
                        tmp1.cnt_r--;
                        tmp1.x=tx;
                        tmp1.y=ty;
                        q.push_back(tmp1);
                    }
                }
                else if(i==3){
                    if(tmp.cnt_l>0){
                        tmp1.cnt_l--;
                        tmp1.x=tx;
                        tmp1.y=ty;
                        q.push_back(tmp1);
                    }
                }
                else{
                    tmp1.x=tx;
                    tmp1.y=ty;
                    q.push_front(tmp1);
                }
            }
        } 
    }
    printf("%d\n",ans);
}
int main(){
    scanf("%d%d",&n,&m);
    scanf("%d%d",&r,&c);
    scanf("%d%d",&rr,&cc);
    for(int i=1;i<=n;i++)
        scanf("%s",s[i]+1);
    bfs(); 
}