답안 #51597

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
51597 2018-06-19T03:02:03 Z model_code Mecho (IOI09_mecho) C++
46 / 100
20 ms 1420 KB
/**
 * A binary search solution for IOI 2009 problem "mecho"
 *
 * This solution should score 100%
 *
 * Carl Hultquist, [email protected]
 */

#include <iostream>
#include <string>
#include <cstdlib>
#include <fstream>
#include <vector>
#include <utility>
#include <memory.h>
#include <deque>

using namespace std;

#define MAX_N 200

int cx[4] = {1, -1, 0, 0};
int cy[4] = {0, 0, 1, -1};

char mainMap[MAX_N][MAX_N];
bool reachable[MAX_N][MAX_N];

// The time that it takes the bees to reach any cell in the map
int beeDistance[MAX_N][MAX_N];

int n, s;
int dx, dy;
int mx, my;

/**
 * Tests if Mecho is able to reach his home after staying with
 * the honey for the given delay time.
 */
bool test(int delay)
{
    // Check if the bees catch Mecho whilst he is still with
    // the honey.
    if (delay * s >= beeDistance[mx][my])
        return false;

    // Initialise data structures -- at the beginning of the search,
    // Mecho has only reached the cell with the honey. Note that it
    // is possible for the bees to catch Mecho at the honey -- but
    // we checked for this case above, and so if we reach this point
    // we know that Mecho is safe with the honey after the given
    // delay.
    memset(reachable, 0, sizeof(reachable));
    deque<pair<int, pair<int, int> > > q;
    q.push_back(make_pair(delay * s, make_pair(mx, my)));
    reachable[mx][my] = true;

    // Now do the main loop to see what other cells Mecho can reach.
    while (!q.empty())
    {
        int distance = q.front().first;
        int x = q.front().second.first;
        int y = q.front().second.second;

        q.pop_front();

        // If Mecho has reached his home, then we are done.
        if (mainMap[x][y] == 'D')
            return true;

        // Check neighbouring cells
        for (int c = 0; c < 4; c++)
        {
            int nx = x + cx[c];
            int ny = y + cy[c];

            // Check that the cell is valid, that it is not a tree, and
            // that Mecho can get here before the bees.
            if (nx < 0 || nx >= n || ny < 0 || ny >= n || mainMap[nx][ny] == 'T' || (distance + 1) >= beeDistance[nx][ny] || reachable[nx][ny])
                continue;

            // All OK, so add it to the queue
            q.push_back(make_pair(distance + 1, make_pair(nx, ny)));
            reachable[nx][ny] = true;
        }
    }

    // If we reach here, then Mecho was unable to reach his home.
    return false;
}
int main(int argc, char **argv)
{
    // Read in the data
    cin >> n >> s;

    deque<pair<int, int> > bq;
    memset(beeDistance, -1, sizeof(beeDistance));

    for (int i = 0; i < n; i++)
    {
        cin >> ws;
        for (int j = 0; j < n; j++)
        {
            cin >> mainMap[i][j];
            if (mainMap[i][j] == 'H')
            {
                bq.push_back(make_pair(i, j));
                beeDistance[i][j] = 0;
            }
            else if (mainMap[i][j] == 'M')
            {
                mx = i;
                my = j;

                // Bees can travel through the location of the honey
                mainMap[i][j] = 'G';
            }
            else if (mainMap[i][j] == 'D')
            {
                dx = i;
                dy = j;
            }
        }
    }

    // Precompute the time that it takes the bees to reach any other
    // cell in the map.
    while (!bq.empty())
    {
        int x = bq.front().first;
        int y = bq.front().second;

        bq.pop_front();

        for (int c = 0; c < 4; c++)
        {
            int nx = x + cx[c];
            int ny = y + cy[c];

            if (nx < 0 || nx >= n || ny < 0 || ny >= n || mainMap[nx][ny] != 'G' || beeDistance[nx][ny] != -1)
                continue;

            beeDistance[nx][ny] = beeDistance[x][y] + s;
            bq.push_back(make_pair(nx, ny));
        }
    }

    // The bees can never enter Mecho's home, so set this to a large
    // sentinel value.
    beeDistance[dx][dy] = n * n * s;

    // Binary search to find the maximum delay time.
    int low = -1, high = 2 * n * n;
    while (high - low > 1)
    {
        int mid = (low + high) >> 1;
        if (test(mid))
            low = mid;
        else
            high = mid;
    }

    cout << low << endl;
    return 0;
}
# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 504 KB Output is correct
2 Correct 2 ms 504 KB Output is correct
3 Correct 2 ms 536 KB Output is correct
4 Correct 2 ms 588 KB Output is correct
5 Correct 2 ms 652 KB Output is correct
6 Correct 2 ms 652 KB Output is correct
7 Runtime error 13 ms 1028 KB Execution killed with signal 11 (could be triggered by violating memory limits)
8 Correct 2 ms 1092 KB Output is correct
9 Correct 2 ms 1092 KB Output is correct
10 Correct 2 ms 1092 KB Output is correct
11 Correct 2 ms 1220 KB Output is correct
12 Correct 2 ms 1220 KB Output is correct
13 Correct 2 ms 1220 KB Output is correct
14 Correct 3 ms 1220 KB Output is correct
15 Correct 2 ms 1220 KB Output is correct
16 Correct 2 ms 1220 KB Output is correct
17 Correct 2 ms 1220 KB Output is correct
18 Correct 2 ms 1220 KB Output is correct
19 Correct 2 ms 1220 KB Output is correct
20 Correct 2 ms 1220 KB Output is correct
21 Correct 2 ms 1220 KB Output is correct
22 Correct 3 ms 1220 KB Output is correct
23 Correct 3 ms 1220 KB Output is correct
24 Correct 2 ms 1220 KB Output is correct
25 Correct 3 ms 1220 KB Output is correct
26 Correct 3 ms 1220 KB Output is correct
27 Correct 3 ms 1220 KB Output is correct
28 Correct 3 ms 1220 KB Output is correct
29 Correct 2 ms 1220 KB Output is correct
30 Correct 3 ms 1220 KB Output is correct
31 Correct 3 ms 1220 KB Output is correct
32 Correct 3 ms 1220 KB Output is correct
33 Runtime error 8 ms 1220 KB Execution killed with signal 11 (could be triggered by violating memory limits)
34 Runtime error 8 ms 1220 KB Execution killed with signal 11 (could be triggered by violating memory limits)
35 Runtime error 10 ms 1256 KB Execution killed with signal 11 (could be triggered by violating memory limits)
36 Runtime error 8 ms 1256 KB Execution killed with signal 11 (could be triggered by violating memory limits)
37 Runtime error 10 ms 1256 KB Execution killed with signal 11 (could be triggered by violating memory limits)
38 Runtime error 8 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
39 Runtime error 10 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
40 Runtime error 9 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
41 Runtime error 9 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
42 Runtime error 14 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
43 Runtime error 9 ms 1272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
44 Runtime error 9 ms 1276 KB Execution killed with signal 11 (could be triggered by violating memory limits)
45 Runtime error 10 ms 1276 KB Execution killed with signal 11 (could be triggered by violating memory limits)
46 Runtime error 16 ms 1276 KB Execution killed with signal 11 (could be triggered by violating memory limits)
47 Runtime error 12 ms 1276 KB Execution killed with signal 11 (could be triggered by violating memory limits)
48 Runtime error 12 ms 1308 KB Execution killed with signal 11 (could be triggered by violating memory limits)
49 Runtime error 11 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
50 Runtime error 11 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
51 Runtime error 12 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
52 Runtime error 11 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
53 Runtime error 12 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
54 Runtime error 12 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
55 Runtime error 14 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
56 Runtime error 12 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
57 Runtime error 13 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
58 Runtime error 13 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
59 Runtime error 14 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
60 Runtime error 14 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
61 Runtime error 14 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
62 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
63 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
64 Runtime error 16 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
65 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
66 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
67 Runtime error 16 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
68 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
69 Runtime error 14 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
70 Runtime error 13 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
71 Runtime error 18 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
72 Runtime error 17 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
73 Runtime error 15 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
74 Runtime error 16 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
75 Runtime error 20 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
76 Runtime error 18 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
77 Runtime error 17 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
78 Runtime error 16 ms 1340 KB Execution killed with signal 11 (could be triggered by violating memory limits)
79 Runtime error 15 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
80 Runtime error 13 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
81 Runtime error 14 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
82 Runtime error 14 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
83 Runtime error 14 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
84 Runtime error 13 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
85 Runtime error 17 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
86 Runtime error 13 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
87 Runtime error 13 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
88 Runtime error 19 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
89 Runtime error 15 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
90 Runtime error 14 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
91 Runtime error 14 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)
92 Runtime error 13 ms 1420 KB Execution killed with signal 11 (could be triggered by violating memory limits)