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Submission #484201

# Submission time Handle Problem Language Result Execution time Memory
484201 2021-11-02T11:33:23 Z nehasane Mecho (IOI09_mecho) C++14
100 / 100
 645 ms 7748 KB 
#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 800;
vector <string> field(MAX_N);
bool bees_visited[MAX_N][MAX_N], mecho_visited[MAX_N][MAX_N];
int mecho_dis[MAX_N][MAX_N], bees_dis[MAX_N][MAX_N];
queue <pair <int, int>> mecho_q, bees_q;
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};
int n, s;
bool valid_sq(int x, int y){
    if (x >= 0 && x < n && y >= 0 && y < n && (field[x][y] == 'G' || field[x][y] == 'M'))
        return true;
    return false;
}
int main()
{
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    cin >> n >> s;
    for (int i = 0; i < n; i++)
        cin >> field[i];
    vector <pair <int, int>> hives;
    int mechox, mechoy, home_x, home_y;
    //find starting points position
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            if (field[i][j] == 'M'){
                mechox = i;
                mechoy = j;
            }else if (field[i][j] == 'H'){
                hives.push_back({i, j});
            }else if (field[i][j] == 'D'){
                home_x = i;
                home_y = j;
            }
        }
    }
    int l = 0, r = n*n;
    while (l <= r){
        int eating_time = (l + r) / 2;
        memset(bees_visited, false, sizeof(bees_visited));
        memset(mecho_visited, false, sizeof(mecho_visited));
        memset(bees_dis, 0, sizeof(bees_dis));
        memset(mecho_dis, 0, sizeof(mecho_dis));
        //move bees
        for (auto i : hives){
            bees_q.push({i.first, i.second});
            bees_visited[i.first][i.second] = true;
        }
        while (!bees_q.empty()){
            int x = bees_q.front().first, y = bees_q.front().second;
            bees_q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                if (valid_sq(nx, ny) && !bees_visited[nx][ny]){
                    bees_dis[nx][ny] = bees_dis[x][y] + 1;    
                    bees_q.push({nx, ny});
                    bees_visited[nx][ny] = true;
                }
            }
        }
        mecho_q.push({mechox, mechoy});
        mecho_visited[mechox][mechoy] = true;
        if (bees_dis[mechox][mechoy] <= eating_time)
            mecho_q.pop();
        while (!mecho_q.empty()){
            int x = mecho_q.front().first, y = mecho_q.front().second;
            mecho_q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                if (valid_sq(nx, ny) && !mecho_visited[nx][ny] && (mecho_dis[x][y] + 1) / s < bees_dis[nx][ny] - eating_time){
                    mecho_visited[nx][ny] = true;
                    mecho_q.push({nx, ny});
                    mecho_dis[nx][ny] = mecho_dis[x][y] + 1;
                }
            }
        }
        bool mecho_reached = false;
        for (int i = 0; i < 4; i++){
            int nx = home_x+ dx[i], ny = home_y + dy[i];
            if (valid_sq(nx, ny) && (mecho_dis[nx][ny] / s) < bees_dis[nx][ny] - eating_time && mecho_visited[nx][ny])
                mecho_reached = true;
        }
        if (mecho_reached)
            l = eating_time + 1;
        else
            r = eating_time - 1;
        }
    cout << l - 1 << '\n';
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:65:36: warning: 'mechoy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   65 |         if (bees_dis[mechox][mechoy] <= eating_time)
      |             ~~~~~~~~~~~~~~~~~~~~~~~^
mecho.cpp:65:36: warning: 'mechox' may be used uninitialized in this function [-Wmaybe-uninitialized]
mecho.cpp:81:37: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   81 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                     ^~
mecho.cpp:81:17: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   81 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                 ^~

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 6476 KB Output is correct
2 Correct 3 ms 6476 KB Output is correct
3 Correct 3 ms 6572 KB Output is correct
4 Correct 4 ms 6476 KB Output is correct
5 Correct 3 ms 6476 KB Output is correct
6 Correct 3 ms 6476 KB Output is correct
7 Correct 469 ms 7440 KB Output is correct
8 Correct 4 ms 6504 KB Output is correct
9 Correct 4 ms 6476 KB Output is correct
10 Correct 4 ms 6476 KB Output is correct
11 Correct 4 ms 6476 KB Output is correct
12 Correct 6 ms 6476 KB Output is correct
13 Correct 6 ms 6476 KB Output is correct
14 Correct 6 ms 6476 KB Output is correct
15 Correct 5 ms 6476 KB Output is correct
16 Correct 4 ms 6476 KB Output is correct
17 Correct 5 ms 6576 KB Output is correct
18 Correct 5 ms 6476 KB Output is correct
19 Correct 5 ms 6476 KB Output is correct
20 Correct 7 ms 6476 KB Output is correct
21 Correct 5 ms 6576 KB Output is correct
22 Correct 5 ms 6476 KB Output is correct
23 Correct 5 ms 6476 KB Output is correct
24 Correct 5 ms 6476 KB Output is correct
25 Correct 5 ms 6476 KB Output is correct
26 Correct 7 ms 6512 KB Output is correct
27 Correct 7 ms 6476 KB Output is correct
28 Correct 7 ms 6476 KB Output is correct
29 Correct 6 ms 6476 KB Output is correct
30 Correct 6 ms 6476 KB Output is correct
31 Correct 6 ms 6476 KB Output is correct
32 Correct 7 ms 6476 KB Output is correct
33 Correct 37 ms 6732 KB Output is correct
34 Correct 36 ms 6732 KB Output is correct
35 Correct 71 ms 6732 KB Output is correct
36 Correct 46 ms 6660 KB Output is correct
37 Correct 57 ms 6760 KB Output is correct
38 Correct 88 ms 6732 KB Output is correct
39 Correct 56 ms 6732 KB Output is correct
40 Correct 61 ms 6732 KB Output is correct
41 Correct 119 ms 6732 KB Output is correct
42 Correct 75 ms 6988 KB Output is correct
43 Correct 82 ms 7036 KB Output is correct
44 Correct 147 ms 7044 KB Output is correct
45 Correct 90 ms 6988 KB Output is correct
46 Correct 84 ms 6988 KB Output is correct
47 Correct 173 ms 7088 KB Output is correct
48 Correct 100 ms 7124 KB Output is correct
49 Correct 105 ms 7116 KB Output is correct
50 Correct 199 ms 7116 KB Output is correct
51 Correct 122 ms 7128 KB Output is correct
52 Correct 122 ms 7200 KB Output is correct
53 Correct 253 ms 7192 KB Output is correct
54 Correct 143 ms 7232 KB Output is correct
55 Correct 137 ms 7188 KB Output is correct
56 Correct 306 ms 7364 KB Output is correct
57 Correct 160 ms 7244 KB Output is correct
58 Correct 156 ms 7276 KB Output is correct
59 Correct 351 ms 7292 KB Output is correct
60 Correct 188 ms 7224 KB Output is correct
61 Correct 181 ms 7256 KB Output is correct
62 Correct 410 ms 7364 KB Output is correct
63 Correct 514 ms 7244 KB Output is correct
64 Correct 645 ms 7332 KB Output is correct
65 Correct 562 ms 7368 KB Output is correct
66 Correct 532 ms 7244 KB Output is correct
67 Correct 525 ms 7316 KB Output is correct
68 Correct 508 ms 7372 KB Output is correct
69 Correct 514 ms 7380 KB Output is correct
70 Correct 475 ms 7364 KB Output is correct
71 Correct 502 ms 7372 KB Output is correct
72 Correct 453 ms 7372 KB Output is correct
73 Correct 435 ms 7748 KB Output is correct
74 Correct 438 ms 7628 KB Output is correct
75 Correct 492 ms 7628 KB Output is correct
76 Correct 445 ms 7628 KB Output is correct
77 Correct 445 ms 7748 KB Output is correct
78 Correct 464 ms 7620 KB Output is correct
79 Correct 440 ms 7580 KB Output is correct
80 Correct 457 ms 7592 KB Output is correct
81 Correct 462 ms 7620 KB Output is correct
82 Correct 463 ms 7500 KB Output is correct
83 Correct 480 ms 7548 KB Output is correct
84 Correct 474 ms 7564 KB Output is correct
85 Correct 529 ms 7556 KB Output is correct
86 Correct 483 ms 7492 KB Output is correct
87 Correct 484 ms 7552 KB Output is correct
88 Correct 461 ms 7500 KB Output is correct
89 Correct 483 ms 7620 KB Output is correct
90 Correct 464 ms 7500 KB Output is correct
91 Correct 471 ms 7500 KB Output is correct
92 Correct 499 ms 7496 KB Output is correct