1130C - Connect.cpp

#include<bits/stdc++.h>
using namespace std;


//{
#define si(a) scanf("%d",&a)
#define sii(a,b) scanf("%d %d",&a,&b);
#define siii(a,b,c) scanf("%d %d %d",&a,&b,&c);

#define sl(a) scanf("%lld",&a)
#define sll(a,b) scanf("%lld %lld",&a,&b);
#define slll(a,b,c) scanf("%lld %lld %lld",&a,&b,&c);

#define outi(a) printf("%d\n",a)
#define outii(a,b) printf("%d %d\n",a,b)
#define outis(a) printf(" %d",a)

#define outl(a) printf("%lld\n",a)
#define outll(a,b) printf("%lld %lld\n",a,b)
#define outls(a) printf(" %lld",a)

#define cel(n,k) ((n-1)/k+1)
#define sets(a) memset(a, -1, sizeof(a))
#define clr(a) memset(a, 0, sizeof(a))
#define max(a,b) ((a)>(b)? (a):(b))
#define min(a,b) ((a)<(b)? (a):(b))
#define fr(n) for(int i=0;i<n;i++)
#define fr1(n) for(int i=1;i<=n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define mp make_pair
#define ff first
#define ss second
#define INF 10000007
#define fastIO() ios_base::sync_with_stdio(false); cin.tie(NULL);

typedef long long i64;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<long long,long long> pll;
//}


int vis[55][55], water[55][55], n, edges, cycle=0;

int dr[]= {1,0,-1,0};
int dc[]= {0,1,0,-1};

vector<pii> reach_s, reach_d;

int isValid(int x, int y){
    return !vis[x][y] && x>=1 && y>=1 && x<=n && y<=n && !water[x][y];
}

void dfs(int x, int y){
    reach_s.pb(mp(x,y));
    vis[x][y]= 1;

    fr(4) {
        pii nd = mp(x + dr[i], y+dc[i]);

        if (isValid(nd.ff,nd.ss)) {
            vis[nd.ff][nd.ss]= 1;
            dfs(nd.ff,nd.ss);
        }
    }
}

void ddfs(int x, int y){
    reach_d.pb(mp(x,y));
    vis[x][y]= 1;

    fr(4) {
        pii nd = mp(x + dr[i], y+dc[i]);

        if (isValid(nd.ff,nd.ss)) {
            vis[nd.ff][nd.ss]= 1;
            ddfs(nd.ff,nd.ss);
        }
    }
}

int getBridge(){
    int mini= 1e9;

    for(pii s: reach_s){
        for(pii d: reach_d){
            int dist= (s.ff-d.ff)*(s.ff-d.ff)+ (s.ss-d.ss)*(s.ss-d.ss);

            if(!dist)  return 0;

            mini= min(mini,dist);
        }
    }

    return mini;
}

main(){
    int a, b, x, y;

    si(n);

    sii(a,b);
    sii(x,y);

    fr1(n){
        for(int j=1;j<=n;j++){
            scanf("%1d",&water[i][j]);
        }
    }


    clr(vis), dfs(a,b);
    clr(vis), ddfs(x,y);

    /*fr(reach_s.size())
        outii(reach_s[i].ff,reach_s[i].ss);

    puts("----");

    fr(reach_d.size())
        outii(reach_d[i].ff,reach_d[i].ss);*/

    outi(getBridge());
}