版权声明：来自星空计算机团队(QQ群：134826825)——申屠志刚 https://blog.csdn.net/weixin_43272781/article/details/85936690
https://ac.nowcoder.com/acm/contest/338/B
题解：BFS裸题
/*
*@Author: STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=10000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,q,ans;
int a[N][N];
char str;
int x,y;
int vis[110][110];
int b[][2]={1,0,0,1,-1,0,0,-1};
struct node
{
int x;
int y;
int lev;
}front1,tmp,start,end1;
queue <node>Q;
int bfs(node s,node e){
while(!Q.empty())
Q.pop();
Q.push(s);
while(!Q.empty()){
front1=Q.front();
Q.pop();
//cout<<front1.x<<" "<<front1.y<<" "<<front1.lev<<endl;
for(int i=0;i<4;i++){
tmp.x=b[i][0]+front1.x;
tmp.y=b[i][1]+front1.y;
tmp.lev=front1.lev;
tmp.lev++;
if(e.x==tmp.x&&e.y==tmp.y){
return tmp.lev;
}
if(tmp.x>=1&&tmp.x<=n&&tmp.y>=1&&tmp.y<=m&&a[tmp.x][tmp.y]!=1&&vis[tmp.x][tmp.y]==0){
vis[tmp.x][tmp.y]=1;//cout<<tmp.x<<" "<<tmp.y<<" "<<tmp.lev<<endl;
Q.push(tmp);
}
}
}
return -1;
}
int main()
{
#ifdef DEBUG
freopen("input.in", "r", stdin);
//freopen("output.out", "w", stdout);
#endif
scanf("%d%d",&n,&m);
scanf("%d%d",&x,&y);
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
scanf("%d",&a[i][j]);
vis[1][1]=1;
start.x=1;
start.y=1;
start.lev=0;
end1.x=x;
end1.y=y;
cout<<bfs(start,end1)<<endl;
//cout << "Hello world!" << endl;
return 0;
}