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Submission #484160

# Submission time Handle Problem Language Result Execution time Memory
484160 2021-11-02T08:38:53 Z nehasane Mecho (IOI09_mecho) C++14
100 / 100
 669 ms 10180 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], eating_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 startx, starty, home_x, home_y;
    //find Mecho's position
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            if (field[i][j] == 'M'){
                startx = i;
                starty = 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]){
                    if (eating_dis[x][y] < eating_time){
                        eating_dis[nx][ny] = eating_dis[x][y] + 1;
                    }else{
                        bees_dis[nx][ny] = bees_dis[x][y] + 1;
                        eating_dis[nx][ny] = INT_MAX;
                    }
                    bees_q.push({nx, ny});
                    bees_visited[nx][ny] = true;
                }
            }
        }
        mecho_q.push({startx, starty});
        mecho_visited[startx][starty] = true;
        if (eating_dis[startx][starty] != INT_MAX)
            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]){
                    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] > (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:75:38: warning: 'starty' may be used uninitialized in this function [-Wmaybe-uninitialized]
   75 |         if (eating_dis[startx][starty] != INT_MAX)
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~^
mecho.cpp:75:38: warning: 'startx' may be used uninitialized in this function [-Wmaybe-uninitialized]
mecho.cpp:91:37: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   91 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                     ^~
mecho.cpp:91:17: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   91 |             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 4 ms 6476 KB Output is correct
3 Correct 3 ms 6476 KB Output is correct
4 Correct 6 ms 6604 KB Output is correct
5 Correct 6 ms 6604 KB Output is correct
6 Correct 6 ms 6612 KB Output is correct
7 Correct 518 ms 9948 KB Output is correct
8 Correct 6 ms 6604 KB Output is correct
9 Correct 5 ms 6732 KB Output is correct
10 Correct 7 ms 6604 KB Output is correct
11 Correct 4 ms 6604 KB Output is correct
12 Correct 7 ms 6740 KB Output is correct
13 Correct 6 ms 6732 KB Output is correct
14 Correct 6 ms 6732 KB Output is correct
15 Correct 5 ms 6604 KB Output is correct
16 Correct 5 ms 6604 KB Output is correct
17 Correct 5 ms 6604 KB Output is correct
18 Correct 5 ms 6604 KB Output is correct
19 Correct 5 ms 6604 KB Output is correct
20 Correct 4 ms 6604 KB Output is correct
21 Correct 5 ms 6604 KB Output is correct
22 Correct 5 ms 6604 KB Output is correct
23 Correct 5 ms 6732 KB Output is correct
24 Correct 5 ms 6732 KB Output is correct
25 Correct 6 ms 6732 KB Output is correct
26 Correct 6 ms 6732 KB Output is correct
27 Correct 6 ms 6732 KB Output is correct
28 Correct 7 ms 6732 KB Output is correct
29 Correct 7 ms 6700 KB Output is correct
30 Correct 7 ms 6812 KB Output is correct
31 Correct 9 ms 6732 KB Output is correct
32 Correct 8 ms 6732 KB Output is correct
33 Correct 51 ms 7804 KB Output is correct
34 Correct 40 ms 7856 KB Output is correct
35 Correct 100 ms 7832 KB Output is correct
36 Correct 53 ms 8012 KB Output is correct
37 Correct 52 ms 7956 KB Output is correct
38 Correct 104 ms 8016 KB Output is correct
39 Correct 67 ms 8140 KB Output is correct
40 Correct 86 ms 8100 KB Output is correct
41 Correct 135 ms 8192 KB Output is correct
42 Correct 80 ms 8620 KB Output is correct
43 Correct 102 ms 8524 KB Output is correct
44 Correct 186 ms 8624 KB Output is correct
45 Correct 97 ms 8828 KB Output is correct
46 Correct 90 ms 8812 KB Output is correct
47 Correct 239 ms 8828 KB Output is correct
48 Correct 115 ms 9036 KB Output is correct
49 Correct 117 ms 9024 KB Output is correct
50 Correct 247 ms 9084 KB Output is correct
51 Correct 128 ms 9164 KB Output is correct
52 Correct 137 ms 9264 KB Output is correct
53 Correct 367 ms 9164 KB Output is correct
54 Correct 150 ms 9420 KB Output is correct
55 Correct 153 ms 9460 KB Output is correct
56 Correct 367 ms 9356 KB Output is correct
57 Correct 167 ms 9548 KB Output is correct
58 Correct 171 ms 9668 KB Output is correct
59 Correct 393 ms 9548 KB Output is correct
60 Correct 198 ms 9840 KB Output is correct
61 Correct 254 ms 9796 KB Output is correct
62 Correct 434 ms 9844 KB Output is correct
63 Correct 535 ms 9844 KB Output is correct
64 Correct 659 ms 9924 KB Output is correct
65 Correct 565 ms 9804 KB Output is correct
66 Correct 542 ms 9924 KB Output is correct
67 Correct 553 ms 9800 KB Output is correct
68 Correct 531 ms 9872 KB Output is correct
69 Correct 545 ms 9872 KB Output is correct
70 Correct 484 ms 9804 KB Output is correct
71 Correct 522 ms 9932 KB Output is correct
72 Correct 483 ms 9872 KB Output is correct
73 Correct 445 ms 10136 KB Output is correct
74 Correct 585 ms 10140 KB Output is correct
75 Correct 525 ms 10180 KB Output is correct
76 Correct 497 ms 10056 KB Output is correct
77 Correct 580 ms 10136 KB Output is correct
78 Correct 500 ms 10032 KB Output is correct
79 Correct 483 ms 10136 KB Output is correct
80 Correct 540 ms 10104 KB Output is correct
81 Correct 495 ms 10100 KB Output is correct
82 Correct 584 ms 10052 KB Output is correct
83 Correct 579 ms 10172 KB Output is correct
84 Correct 493 ms 10068 KB Output is correct
85 Correct 669 ms 10064 KB Output is correct
86 Correct 599 ms 10064 KB Output is correct
87 Correct 512 ms 10060 KB Output is correct
88 Correct 617 ms 10064 KB Output is correct
89 Correct 525 ms 10052 KB Output is correct
90 Correct 503 ms 10008 KB Output is correct
91 Correct 577 ms 10108 KB Output is correct
92 Correct 543 ms 10096 KB Output is correct