4b-4.cpp

#include <iostream>
#include <queue>
using namespace std;

int peta[150][150];
int n,m;
int mn = 99999;

int main()
{
    cin >> n >> m;
    for (int i=0; i<n; i++){
        for (int j=0; j<m; j++){
            cin >> peta[i][j];
        }
    }
    int a,b;
    cin >> a >> b;
    a--; b--;

    queue<int> bfsr;
    queue<int> bfsc;
    queue<int> bfsstepcount;
    bfsr.push(a);
    bfsc.push(b);
    bfsstepcount.push(1);
    while(!bfsr.empty()){
        int r = bfsr.front();
        int c = bfsc.front();
        int sc = bfsstepcount.front();
        bfsr.pop();
        bfsc.pop();
        bfsstepcount.pop();

        if ((r <= 0) || (r >= n-1) || (c <= 0) || (c >= m-1)){
            mn = sc;
            break;
        }

            if (peta[r-1][c] == 0){
                bfsr.push(r-1);
                bfsc.push(c);
                bfsstepcount.push(sc+1);
            }

            if (peta[r+1][c] == 0){
                bfsr.push(r+1);
                bfsc.push(c);
                bfsstepcount.push(sc+1);
            }

            if (peta[r][c-1] == 0){
                bfsr.push(r);
                bfsc.push(c-1);
                bfsstepcount.push(sc+1);
            }

            if (peta[r][c+1] == 0){
                bfsr.push(r);
                bfsc.push(c+1);
                bfsstepcount.push(sc+1);
            }
    }

    cout << mn << endl;
}