题解 | 走迷宫

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define quick ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int inf = 0x3f3f3f3f, maxn = 2e5 + 5, mod = 998252334;
inline int read() {
    int s = 0, w = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9') {
        if (ch == '-')w = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')s = s * 10 + ch - '0', ch = getchar();
    return s * w;
}
struct node{
    int x,y,step;
};
int dx[]={1,-1,0,0};
int dy[]={0,0,1,-1};
int n,m;
void solve() {
    n=read();m=read();
    vector<vector<int>>grid(n+1,vector<int>(m+1));
    int xs,ys,xt,yt;
    xs=read(),ys=read(),xt=read(),yt=read();
    char t;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>t;
            if(t=='*'){
                grid[i][j]=1;
                if(i==xt&&j==yt){
                    cout<<-1<<endl;
                    return;
                }
            }
        }
    }

    // for(int i=1;i<=n;i++){
    //     for(int j=1;j<=m;j++){
    //         cout<<grid[i][j]<<' ';
    //     }
    //     cout<<endl;
    // }

    queue<node>que;
    que.push({xs,ys,0});
    while(!que.empty()){
        node k=que.front();
        que.pop();
        for(int i=0;i<4;i++){
            node nd;
            nd.x=k.x+dx[i];
            nd.y=k.y+dy[i];
            if(nd.x==xt&&nd.y==yt){
                cout<<k.step+1<<endl;
                return;
            }
            if(nd.x<1||nd.y<1||nd.x>n||nd.y>m) continue;
            if(grid[nd.x][nd.y]==1) continue;
            grid[nd.x][nd.y]=1;
            nd.step=k.step+1;
            que.push(nd);
        }
    }
    cout<<-1<<endl;
}
signed main() {
    int t = 1;
//  cin>>t;
    while (t--) {
        solve();
    }
    return 0;
}