Submission #490141

#	Time	Username	Problem	Language	Result	Execution time	Memory
490141		JerryLiu06	Portals (BOI14_portals)	C++17	20 / 100	5 ms	2764 KiB

portals

// https://oj.uz/problem/view/BOI14_portals
 
#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(0);
#define FASTIOF ios_base::sync_with_stdio(false); fin.tie(0);
 
#define mp make_pair
#define f first
#define s second
 
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert 
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
 
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
 
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
 
template<class T> void remDup(vector<T>& v) { sor(v); v.erase(unique(all(v)), v.end()); }
 
const int MOD = 1e9 + 7;
const int MX = 1e3 + 10;
const ll INF = 1e18;

// DIR: 0 = north, 1 = east, 2 = south, 3 = west

const int DIR[4][2] = { {-1, 0}, {0, 1}, {1, 0}, {0, -1} };

int R, C, SX, SY, CX, CY; char G[MX][MX]; array<pi, 4> nxt[MX][MX];

bool isWall(int i, int j) {
    return i <= 0 || i > R || j <= 0 || j > C || G[i][j] == '#';
}

int main() {
    FASTIO;

    cin >> R >> C;

    FOR(i, 1, R + 1) {
        FOR(j, 1, C + 1) {
            cin >> G[i][j];

            if (G[i][j] == 'S') {
                SX = i, SY = j;
            }
            if (G[i][j] == 'C') {
                CX = i, CY = j; 
            }
        }
    }
    FOR(j, 1, C + 1) {
        pi lst = {1, j};

        FOR(i, 1, R + 1) {
            if (G[i][j] != '#') {
                nxt[i][j][0] = lst;
            }
            else {
                lst = {i + 1, j};
            }
        }
        lst = {R, j};

        ROF(i, 1, R + 1) {
            if (G[i][j] != '#') {
                nxt[i][j][2] = lst;
            }
            else {
                lst = {i - 1, j};
            }
        }
    }
    FOR(i, 1, R + 1) {
        pi lst = {i, C};

        ROF(j, 1, C + 1) {
            if (G[i][j] != '#') {
                nxt[i][j][1] = lst;
            }
            else {
                lst = {i, j - 1};
            }
        }
        lst = {i, 1};

        FOR(j, 1, C + 1) {
            if (G[i][j] != '#') {
                nxt[i][j][3] = lst;
            }
            else {
                lst = {i, j + 1};
            }
        }
    }
    // FOR(i, 1, R + 1) {
    //     FOR(j, 1, C + 1) {
    //         cout << "{" << nxt[i][j][1].f << ", " << nxt[i][j][1].s << "} ";
    //     }
    //     cout << "\n";
    // }
    int minDist[R + 1][C + 1];

    FOR(i, 1, R + 1) {
        FOR(j, 1, C + 1) {
            minDist[i][j] = MOD;
        }
    }
    queue<pi> Q; 
    Q.push({SX, SY});

    minDist[SX][SY] = 0;

    while (!Q.empty()) {
        pi cur = Q.front(); Q.pop();

        if (cur.f == CX && cur.s == CY) {
            return cout << minDist[CX][CY], 0;
        }
        bool nextToWall = false;

        F0R(i, 4) {
            int nX = cur.f + DIR[i][0];
            int nY = cur.s + DIR[i][1];

            if (isWall(nX, nY)) {
                nextToWall = true;
                continue;
            }
            if (minDist[nX][nY] != MOD) {
                continue;
            }
            Q.push({nX, nY});
            minDist[nX][nY] = minDist[cur.f][cur.s] + 1;
        }
        if (nextToWall) {
            F0R(i, 4) {
                int nX = nxt[cur.f][cur.s][i].f;
                int nY = nxt[cur.f][cur.s][i].s;

                if (minDist[nX][nY] != MOD) {
                    continue;
                }
                Q.push({nX, nY});
                minDist[nX][nY] = minDist[cur.f][cur.s] + 1;
            }
        }
    }
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30