oj.uz

Submission #726452

# Submission time Handle Problem Language Result Execution time Memory
726452 2023-04-19T00:05:23 Z Tigerpants Portals (BOI14_portals) C++17
100 / 100
 361 ms 93548 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <numeric>
#include <functional>

using namespace std;

typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;

#define rep(i, a, b) for (ll i = a; i < b; i++)
#define mp(a, b) make_pair(a, b)
#define sz(a) a.size()
#define pb(a) push_back(a)

const ll INF = 1000000000;

vvll wall;
vvll dp;
vvll portal[4]; // for each of the 4 directions, get the distance to the wall...

pll start;
pll cake;
ll R, C;
vvb board;

ll dx[4] = {1, 0, -1, 0};
ll dy[4] = {0, 1, 0, -1};

void calc_wall();
void calc_goal();
void calc_portal();

/*
bool dp_compare(pll a, pll b) {
    if (dp[a.first][a.second] == dp[b.first][b.second]) {
        return a < b;
    }
    return dp[a.first][a.second] < dp[b.first][b.second];
}
set<pll, decltype(dp_compare)*> BFS(dp_compare);
*/

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> R >> C;
    board.resize(R + 2);
    char tmp;
    board[0].resize(C + 2);
    board[R + 1].resize(C + 2);
    rep(j, 0, C + 2) {board[0][j] = false; board[R + 1][j] = false;}
    rep(i, 1, R + 1) {
        board[i].resize(C + 2);
        board[i][0] = false;
        board[i][C + 1] = false;
        rep(j, 1, C + 1) {
            cin >> tmp;
            board[i][j] = (tmp != '#');
            if (tmp == 'S') {
                start = mp(i, j);
            }
            if (tmp == 'C') {
                cake = mp(i, j);
            }
        }
    }
    R += 2;
    C += 2;

    wall.resize(R);
    dp.resize(R);
    rep(i, 0, 4) portal[i].resize(R);

    rep(i, 0, R) {
        wall[i].resize(C);
        dp[i].resize(C);
        rep(j, 0, 4) portal[j][i].resize(C);
        rep(j, 0, C) dp[i][j] = INF;
    }

    // calculate supporting values
    calc_wall();
    calc_portal();

    // do BFS in dp graph...
    dp[start.first][start.second] = 0;

    /*
    rep(i, 0, R) {
        rep(j, 0, C) {
            if (board[i][j]) BFS.insert(mp(i, j));
        }
    }
    */

    vvpll BFS(R * C, vpll());
    vvb vis(R, vb(C, false));

    BFS[0].pb(start);

    rep(d, 0, R * C) {
        for (vpll::iterator cur = BFS[d].begin(); cur != BFS[d].end(); cur++) {
            if (vis[cur->first][cur->second]) continue;
            vis[cur->first][cur->second] = true;

            rep(k, 0, 4) {
                // try walking
                pll next = mp(cur->first + dx[k], cur->second + dy[k]);
                if ((board[next.first][next.second]) && (dp[next.first][next.second] > dp[cur->first][cur->second] + 1)) {
                    dp[next.first][next.second] = dp[cur->first][cur->second] + 1;
                    BFS[dp[next.first][next.second]].pb(next);
                }

                // try shooting
                next = mp(cur->first + (dx[k] * portal[k][cur->first][cur->second]), cur->second + (dy[k] * portal[k][cur->first][cur->second]));
                if ((portal[k][cur->first][cur->second] >= 1) && (dp[next.first][next.second] > dp[cur->first][cur->second] + wall[cur->first][cur->second])) {
                    dp[next.first][next.second] = dp[cur->first][cur->second] + wall[cur->first][cur->second];
                    BFS[dp[next.first][next.second]].pb(next);
                }

            }
        }
        BFS[d].clear();
    }

    cout << dp[cake.first][cake.second] << endl;

    return 0;
}

void calc_wall() {
    vvb vis(R, vb(C, false));
    vpll p, q;
    rep(i, 0, R) {
        rep(j, 0, C) {
            if (!board[i][j]) {
                q.pb(mp(i, j));
                wall[i][j] = 0;
                vis[i][j] = true;
            }
        }
    }
    while (!q.empty()) {
        for (vpll::iterator itr = q.begin(); itr != q.end(); itr++) {
            rep(d, 0, 4) {
                pll next = mp(itr->first + dx[d], itr->second + dy[d]);
                if ((next.first == -1) || (next.second == -1) || (next.first == R) || (next.second == C)) continue;
                if (!vis[next.first][next.second]) {
                    vis[next.first][next.second] = true;
                    wall[next.first][next.second] = wall[itr->first][itr->second] + 1;
                    p.pb(next);
                }
            }
        }
        swap(p, q);
        p.clear();
    }
}

ll portal_dp(ll i, ll j, ll k) {
    if (portal[k][i][j] == -2) portal[k][i][j] = portal_dp(i + dx[k], j + dy[k], k) + 1;
    return portal[k][i][j];
}

void calc_portal() {
    // setup before call dp
    rep(i, 0, R) {
        rep(j, 0, C) {
            rep(k, 0, 4) {
                portal[k][i][j] = -1 -(board[i][j]);
            }
        }
    }

    rep(i, 0, R) {
        rep(j, 0, C) {
            rep(k, 0, 4) {
                portal_dp(i, j, k);
            }
        }
    }
}

// There is a (RC)^3 dp
// There is also a (RC)^2 dp: if there are 2 portals then one should b-line to one of them

// For each cell we define the following distances:
// Distance to cell before nearest wall
// Distance to goal
// Then from each cell we can do one of 3 operations:
// Move a step up/down/left/right
// Shoot a portal to a wall up/down/left/right and go to nearest wall to appear at where we shot
// Move to goal
// This gives us a 9*RC dp with RC statest and 9 edges per state...

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 2 ms 468 KB Output is correct
10 Correct 1 ms 596 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 468 KB Output is correct
16 Correct 1 ms 212 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 9 ms 3792 KB Output is correct
6 Correct 9 ms 3792 KB Output is correct
7 Correct 9 ms 3880 KB Output is correct
8 Correct 7 ms 4044 KB Output is correct

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 596 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 9 ms 3792 KB Output is correct
15 Correct 9 ms 3792 KB Output is correct
16 Correct 9 ms 3868 KB Output is correct
17 Correct 11 ms 3872 KB Output is correct
18 Correct 9 ms 3868 KB Output is correct
19 Correct 11 ms 4052 KB Output is correct
20 Correct 10 ms 4052 KB Output is correct
21 Correct 10 ms 3792 KB Output is correct
22 Correct 12 ms 3800 KB Output is correct
23 Correct 8 ms 3800 KB Output is correct
24 Correct 9 ms 4180 KB Output is correct
25 Correct 0 ms 212 KB Output is correct
26 Correct 1 ms 468 KB Output is correct
27 Correct 0 ms 212 KB Output is correct
28 Correct 9 ms 4124 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 9 ms 3824 KB Output is correct
15 Correct 9 ms 3792 KB Output is correct
16 Correct 10 ms 3788 KB Output is correct
17 Correct 10 ms 3876 KB Output is correct
18 Correct 10 ms 3864 KB Output is correct
19 Correct 12 ms 4052 KB Output is correct
20 Correct 9 ms 4052 KB Output is correct
21 Correct 9 ms 3740 KB Output is correct
22 Correct 10 ms 3740 KB Output is correct
23 Correct 8 ms 3800 KB Output is correct
24 Correct 217 ms 84352 KB Output is correct
25 Correct 361 ms 89068 KB Output is correct
26 Correct 240 ms 90652 KB Output is correct
27 Correct 273 ms 90264 KB Output is correct
28 Correct 232 ms 85900 KB Output is correct
29 Correct 241 ms 86040 KB Output is correct
30 Correct 257 ms 85268 KB Output is correct
31 Correct 9 ms 4180 KB Output is correct
32 Correct 252 ms 91172 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 1 ms 576 KB Output is correct
35 Correct 210 ms 86332 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 9 ms 4172 KB Output is correct
38 Correct 226 ms 93548 KB Output is correct
39 Correct 191 ms 81920 KB Output is correct