Cod sursa(job #2094766)

Utilizator laurageorgescuLaura Georgescu laurageorgescu Data 26 decembrie 2017 15:34:26
Problema Car Scor 80
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.5 kb
#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

ifstream fin ("car.in"); ofstream fout ("car.out");

const int nmax = 500;
const int inf = 1 << 30;
const int dl[ 8 ] = {-1, -1, -1, 0, 1, 1, 1, 0};
const int dc[ 8 ] = {-1, 0, 1, 1, 1, 0, -1, -1};

int n, m, ram;
bool v[nmax + 2][nmax + 2];

int stx, sty, fnx, fny;

int c[ 8 ][ 8 ];

int d[nmax + 1][8 * nmax + 1];
bitset<8 * nmax + 1> gata[nmax + 1];

struct str {
    int x, y, k;

    str () {}
    str (int _x, int _y, int _k) {
        x = _x, y = _y, k = _k;
    }
};

vector< str > q[ 5 ];

inline int cst (int x, int y) {
    if (x > y) swap(x, y);
    return min(y - x, 8 - y + x);
}

void extinde (str p, int ind) {
    for (int dir = 0; dir < 8; ++ dir) {
        int x = p.x + dl[ dir ], y = p.y + dc[ dir ];

        if (gata[ x ][8 * y + dir] == 1 || v[ x ][ y ] == 1)
            continue;

        int C = c[ p.k ][ dir ];
        if (d[ x ][8 * y + dir] > d[ p.x ][8 * p.y + p.k] + C) {
            ++ ram;

            d[ x ][8 * y + dir] = d[ p.x ][8 * p.y + p.k] + C;

            int ix = ind + C;
            if (ix >= 5) ix -= 5;
            q[ ix ].push_back(str(x, y, dir));
        }
    }
}

void bfs () {
    ram = 0;

    for (int i = 0; i < 8; ++ i) {
        d[ stx ][8 * sty + i] = 0;
        ++ ram;
        q[ 0 ].push_back(str(stx, sty, i));
    }

    int ind = 0;
    while (ram > 0) {
        while (q[ ind ].empty()) {
            ++ ind;
            if (ind == 5) ind = 0;
        }

        str p = q[ ind ].back(); q[ ind ].pop_back();
        -- ram;

        if (gata[ p.x ][8 * p.y + p.k] == 1)
            continue;
        gata[ p.x ][8 * p.y + p.k] = 1;

        extinde(p, ind);
    }
}

int main () {
    fin >> n >> m >> stx >> sty >> fnx >> fny;

    for (int i = 1; i <= n; ++ i) {
        for (int j = 1; j <= m; ++ j) {
            fin >> v[ i ][ j ];
        }
    }

    for (int i = 0; i < 8; ++ i)
        for (int j = 0; j < 8; ++ j)
            c[ i ][ j ] = cst(i, j);

    for (int i = 0; i <= n + 1; ++ i)
        v[ i ][ 0 ] = v[ i ][m + 1] = 1;
    for (int i = 0; i <= m + 1; ++ i)
        v[ 0 ][ i ] = v[n + 1][ i ] = 1;


    for (int i = 1; i <= n; ++ i)
        for (int j = 1; j <= m; ++ j)
            for (int k = 0; k < 8; ++ k)
                d[ i ][8 * j + k] = inf;

    bfs();


    int ans = inf;
    for (int i = 0; i < 8; ++ i)
        ans = min(ans, d[ fnx ][8 * fny + i]);

    if (ans == inf)
        ans = -1;

    fout << ans << "\n";

    fin.close();
    fout.close();
    return 0;
}