bfs. конь

#include <iostream>
#include <cmath>
#include <vector>
#include <set>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
using ll = long long;
#define pii pair <int, int>
void cv(vector <int> v){
    for (auto x: v) cout<<x<<' ';
    cout<<'\n';
}
int N;
bool in(int x, int y){
    bool a = x < N && x >=0;
    bool b = y < N && y >= 0;
    return a&&b;
}

vector <int> dx = {-2, -2, -1, 1, 2, 2, 1, -1};
vector <int> dy = {-1, 1, 2, 2, 1, -1, -2, -2};
vector <vector <vector <pii> > > dsk(8, vector <vector <pii> > (8));
queue <pii> go1;
pii strt, fin;
vector < vector <pii> > pred;
vector <vector<int>> dst(8, vector <int> (8, -1));
int cnt = 0;
void bfs(){
    dst[strt.first][strt.second] = 0;
    go1.push(strt);
    cout<<"BFS\n";
    while (!go1.empty()){
        auto v = go1.front();
        //cout<<"v= \n";
    //cout<<v.first<<' '<<v.second<<'\n';
        for (auto u: dsk[v.first][v.second]){
            if (dst[u.first][u.second] = -1){
                dst[u.first][u.second] = dst[v.first][v.second] + 1;
                go1.push(u);
                pred[u.first][u.second] = v;
            }
            if (u == fin){
                return;
            }
        }
        go1.pop();
        cnt++;
        //if (cnt == 200) exit(0);
    }
}

int main()
{
    /*ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);*/
    cin>>N;
    dsk.resize(N);
    dst.resize(N);
    for (int i=0;i<N;++i){
        dsk[i].resize(N);
        dst[i].resize(N, -1);
    }
    for (int i = 0; i < N;++i){
        for (int j=0;j<N;++j){
                //cout<<"IJ= "<<i<<" "<<j<<"\n";
            for (int ngb = 0; ngb<8; ++ngb){
                //cout<<"ngb= "<<ngb<<'\n';
                int I = i + dx[ngb];
                int J = j + dy[ngb];
                //cout<<"dx dy = "<<dx[ngb]<<' '<<dy[ngb]<<'\n';
                if (in(I, J)){
                    dsk[i][j].push_back({I, J});
                }
            }//cout<<'\n';
        }
    }
    /*cout<<"\nDESK\n";
    for (int i = 0; i < N;++i){
        for (int j=0;j<N;++j){
                cout<<"IJ= "<<i<<" "<<j<<"\n";
            for (auto ngb: dsk[i][j]){
                cout<<ngb.first<<' '<<ngb.second<<"\n";
            }cout<<"\n";
        }
    }*/

    cin>>strt.first>>strt.second>>fin.first>>fin.second;
    strt.first--;
    strt.second--;
    fin.first--;
    fin.second--;
    bfs();
    cout<<"ans= \n";
    cout<<dst[fin.first][fin.second]<<'\n';
    cout<<"predki\n";
    pii pr = fin;
    vector <pii> ans_pred;
    while (true){
        ans_pred.push_back(pr);
        pr = pred[pr.first][pr.second];
        if (pr == strt) break;
    }
    for (auto x: ans_pred) cout<<x.first<<' '<<x.second<<'\n';
    cout<<'\n';
}