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Submission #484200

# Submission time Handle Problem Language Result Execution time Memory
484200 2021-11-02T11:27:36 Z nehasane Mecho (IOI09_mecho) C++14
100 / 100
 642 ms 7632 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, bool is_mecho){
    if (x >= 0 && x < n && y >= 0 && y < n){
        if (is_mecho && (field[x][y] == 'G' || field[x][y] == 'D' || field[x][y] == 'M'))
            return true;
        else if (!is_mecho && (field[x][y] == 'G' || field[x][y] == 'M'))
            return true;
        return false;
    }
    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, false) && !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, true) && !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, true)){
                if (bees_dis[nx][ny] - eating_time > (mecho_dis[nx][ny] / s) && mecho_visited[nx][ny]){
                    mecho_reached = true;
                    break;
                }
            }
        }
        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:70:36: warning: 'mechoy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   70 |         if (bees_dis[mechox][mechoy] <= eating_time)
      |             ~~~~~~~~~~~~~~~~~~~~~~~^
mecho.cpp:70:36: warning: 'mechox' may be used uninitialized in this function [-Wmaybe-uninitialized]
mecho.cpp:86:37: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   86 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                     ^~
mecho.cpp:86:17: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   86 |             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 4 ms 6604 KB Output is correct
2 Correct 4 ms 6476 KB Output is correct
3 Correct 3 ms 6476 KB Output is correct
4 Correct 3 ms 6476 KB Output is correct
5 Correct 4 ms 6476 KB Output is correct
6 Correct 4 ms 6476 KB Output is correct
7 Correct 481 ms 7440 KB Output is correct
8 Correct 4 ms 6476 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 11 ms 6476 KB Output is correct
13 Correct 6 ms 6476 KB Output is correct
14 Correct 7 ms 6476 KB Output is correct
15 Correct 5 ms 6476 KB Output is correct
16 Correct 6 ms 6476 KB Output is correct
17 Correct 5 ms 6580 KB Output is correct
18 Correct 5 ms 6476 KB Output is correct
19 Correct 4 ms 6476 KB Output is correct
20 Correct 4 ms 6476 KB Output is correct
21 Correct 5 ms 6476 KB Output is correct
22 Correct 5 ms 6476 KB Output is correct
23 Correct 6 ms 6476 KB Output is correct
24 Correct 7 ms 6580 KB Output is correct
25 Correct 9 ms 6580 KB Output is correct
26 Correct 7 ms 6476 KB Output is correct
27 Correct 9 ms 6588 KB Output is correct
28 Correct 7 ms 6560 KB Output is correct
29 Correct 8 ms 6476 KB Output is correct
30 Correct 8 ms 6476 KB Output is correct
31 Correct 7 ms 6512 KB Output is correct
32 Correct 9 ms 6476 KB Output is correct
33 Correct 38 ms 6732 KB Output is correct
34 Correct 38 ms 6752 KB Output is correct
35 Correct 71 ms 6732 KB Output is correct
36 Correct 47 ms 6732 KB Output is correct
37 Correct 48 ms 6732 KB Output is correct
38 Correct 94 ms 6732 KB Output is correct
39 Correct 63 ms 6780 KB Output is correct
40 Correct 89 ms 6732 KB Output is correct
41 Correct 122 ms 6784 KB Output is correct
42 Correct 73 ms 6988 KB Output is correct
43 Correct 74 ms 7052 KB Output is correct
44 Correct 170 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 179 ms 7100 KB Output is correct
48 Correct 124 ms 7116 KB Output is correct
49 Correct 123 ms 7140 KB Output is correct
50 Correct 208 ms 7132 KB Output is correct
51 Correct 123 ms 7116 KB Output is correct
52 Correct 132 ms 7176 KB Output is correct
53 Correct 275 ms 7208 KB Output is correct
54 Correct 147 ms 7244 KB Output is correct
55 Correct 155 ms 7244 KB Output is correct
56 Correct 299 ms 7244 KB Output is correct
57 Correct 164 ms 7276 KB Output is correct
58 Correct 176 ms 7276 KB Output is correct
59 Correct 355 ms 7304 KB Output is correct
60 Correct 199 ms 7312 KB Output is correct
61 Correct 194 ms 7320 KB Output is correct
62 Correct 428 ms 7344 KB Output is correct
63 Correct 532 ms 7336 KB Output is correct
64 Correct 642 ms 7244 KB Output is correct
65 Correct 559 ms 7336 KB Output is correct
66 Correct 516 ms 7232 KB Output is correct
67 Correct 561 ms 7364 KB Output is correct
68 Correct 447 ms 7372 KB Output is correct
69 Correct 498 ms 7372 KB Output is correct
70 Correct 470 ms 7360 KB Output is correct
71 Correct 519 ms 7364 KB Output is correct
72 Correct 452 ms 7356 KB Output is correct
73 Correct 437 ms 7624 KB Output is correct
74 Correct 461 ms 7632 KB Output is correct
75 Correct 489 ms 7628 KB Output is correct
76 Correct 456 ms 7628 KB Output is correct
77 Correct 484 ms 7628 KB Output is correct
78 Correct 477 ms 7600 KB Output is correct
79 Correct 469 ms 7620 KB Output is correct
80 Correct 442 ms 7596 KB Output is correct
81 Correct 486 ms 7500 KB Output is correct
82 Correct 469 ms 7620 KB Output is correct
83 Correct 486 ms 7500 KB Output is correct
84 Correct 474 ms 7588 KB Output is correct
85 Correct 543 ms 7500 KB Output is correct
86 Correct 508 ms 7604 KB Output is correct
87 Correct 486 ms 7560 KB Output is correct
88 Correct 477 ms 7508 KB Output is correct
89 Correct 497 ms 7516 KB Output is correct
90 Correct 478 ms 7496 KB Output is correct
91 Correct 487 ms 7452 KB Output is correct
92 Correct 520 ms 7500 KB Output is correct