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Submission #916970

# Submission time Handle Problem Language Result Execution time Memory
916970 2024-01-26T21:32:57 Z vanea Mecho (IOI09_mecho) C++14
100 / 100
 500 ms 7760 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const int mxN = 801;
int n, s;
vector<string> field(mxN);

int d1[mxN][mxN], d2[mxN][mxN];
bool vis1[mxN][mxN], vis2[mxN][mxN];

vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};

void restart() {
    memset(vis1, false, sizeof vis1);
    memset(vis2, false, sizeof vis2);
    memset(d1, 0, sizeof d1);
    memset(d2, 0, sizeof d2);
}

bool valid(int x, int y) {
    return (x >= 0 && x < n && y >= 0 && y < n && (field[x][y] == 'G' ||
                                    field[x][y] == 'M'));
}

bool reached(int a, int b) {
    return a/s < b;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> s;
    array<int, 2> start, finish;
    vector<array<int, 2>> hives;
    for(int i = 0; i < n; i++) {
        cin >> field[i];
        for(int j = 0; j < n; j++) {
            if(field[i][j] == 'M') start = {i, j};
            else if(field[i][j] == 'H') hives.push_back({i, j});
            else if(field[i][j] == 'D') finish = {i, j};
        }
    }
    int l = 0, r = n * n;
    while(l <= r) {
        int mid = (r+l)/2;
        restart();
        queue<array<int, 2>> q;
        for(auto it : hives) {
            q.push(it);
            vis1[it[0]][it[1]] = true;
        }
        while(!q.empty()) {
            int x = q.front()[0], y = q.front()[1];
            q.pop();
            for(int k = 0; k < 4; k++) {
                int a = x + dx[k], b = y + dy[k];
                if(valid(a, b) && !vis1[a][b]) {
                    vis1[a][b] = true;
                    d1[a][b] = d1[x][y]+1;
                    q.push({a, b});
                }
            }
        }
        q.push(start);
        vis2[start[0]][start[1]] = true;
        if(d1[start[0]][start[1]] <= mid) q.pop();
        while(!q.empty()) {
            int x = q.front()[0], y = q.front()[1];
            q.pop();
            for(int k = 0; k < 4; k++) {
                int a = x + dx[k], b = y + dy[k];
                if(valid(a, b) && !vis2[a][b] && reached(d2[x][y]+1,
                                                         d1[a][b]-mid)) {
                    vis2[a][b] = true;
                    q.push({a, b});
                    d2[a][b] = d2[x][y]+1;
                }
            }
        }
        bool can = false;
        for(int k = 0; k < 4; k++) {
            int a = finish[0]+dx[k], b = finish[1]+dy[k];
            if(valid(a, b) && reached(d2[a][b], d1[a][b]-mid) && vis2[a][b]) {
                can = true;
            }
        }
        if(can) l = mid+1;
        else r = mid-1;
    }
    cout << l-1;
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:84:35: warning: 'finish.std::array<int, 2>::_M_elems[0]' may be used uninitialized in this function [-Wmaybe-uninitialized]
   84 |             int a = finish[0]+dx[k], b = finish[1]+dy[k];
      |                                   ^
mecho.cpp:84:56: warning: 'finish.std::array<int, 2>::_M_elems[1]' may be used uninitialized in this function [-Wmaybe-uninitialized]
   84 |             int a = finish[0]+dx[k], b = finish[1]+dy[k];
      |                                                        ^

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 6744 KB Output is correct
2 Correct 2 ms 6748 KB Output is correct
3 Correct 2 ms 6748 KB Output is correct
4 Correct 2 ms 6748 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 3 ms 6748 KB Output is correct
7 Correct 384 ms 7536 KB Output is correct
8 Correct 3 ms 6744 KB Output is correct
9 Correct 3 ms 6748 KB Output is correct
10 Correct 3 ms 6748 KB Output is correct
11 Correct 3 ms 6748 KB Output is correct
12 Correct 4 ms 6748 KB Output is correct
13 Correct 4 ms 6776 KB Output is correct
14 Correct 4 ms 6748 KB Output is correct
15 Correct 3 ms 6748 KB Output is correct
16 Correct 3 ms 6748 KB Output is correct
17 Correct 3 ms 6748 KB Output is correct
18 Correct 3 ms 6748 KB Output is correct
19 Correct 3 ms 6748 KB Output is correct
20 Correct 3 ms 6748 KB Output is correct
21 Correct 3 ms 6748 KB Output is correct
22 Correct 3 ms 6748 KB Output is correct
23 Correct 4 ms 6748 KB Output is correct
24 Correct 4 ms 6572 KB Output is correct
25 Correct 4 ms 6748 KB Output is correct
26 Correct 4 ms 6748 KB Output is correct
27 Correct 4 ms 6748 KB Output is correct
28 Correct 4 ms 6748 KB Output is correct
29 Correct 4 ms 6748 KB Output is correct
30 Correct 4 ms 6748 KB Output is correct
31 Correct 4 ms 6752 KB Output is correct
32 Correct 4 ms 6748 KB Output is correct
33 Correct 31 ms 6868 KB Output is correct
34 Correct 26 ms 6748 KB Output is correct
35 Correct 60 ms 6748 KB Output is correct
36 Correct 35 ms 6744 KB Output is correct
37 Correct 37 ms 7000 KB Output is correct
38 Correct 81 ms 6744 KB Output is correct
39 Correct 47 ms 6744 KB Output is correct
40 Correct 44 ms 6748 KB Output is correct
41 Correct 100 ms 6956 KB Output is correct
42 Correct 56 ms 7004 KB Output is correct
43 Correct 59 ms 7004 KB Output is correct
44 Correct 121 ms 7000 KB Output is correct
45 Correct 70 ms 6916 KB Output is correct
46 Correct 61 ms 7004 KB Output is correct
47 Correct 158 ms 7068 KB Output is correct
48 Correct 97 ms 7004 KB Output is correct
49 Correct 77 ms 7000 KB Output is correct
50 Correct 169 ms 7004 KB Output is correct
51 Correct 99 ms 7004 KB Output is correct
52 Correct 88 ms 7004 KB Output is correct
53 Correct 200 ms 7004 KB Output is correct
54 Correct 115 ms 7256 KB Output is correct
55 Correct 114 ms 7256 KB Output is correct
56 Correct 237 ms 7256 KB Output is correct
57 Correct 126 ms 7260 KB Output is correct
58 Correct 125 ms 7352 KB Output is correct
59 Correct 314 ms 7508 KB Output is correct
60 Correct 155 ms 7256 KB Output is correct
61 Correct 142 ms 7412 KB Output is correct
62 Correct 325 ms 7448 KB Output is correct
63 Correct 368 ms 7508 KB Output is correct
64 Correct 500 ms 7420 KB Output is correct
65 Correct 411 ms 7416 KB Output is correct
66 Correct 393 ms 7256 KB Output is correct
67 Correct 379 ms 7508 KB Output is correct
68 Correct 364 ms 7460 KB Output is correct
69 Correct 381 ms 7452 KB Output is correct
70 Correct 352 ms 7444 KB Output is correct
71 Correct 398 ms 7444 KB Output is correct
72 Correct 334 ms 7260 KB Output is correct
73 Correct 322 ms 7724 KB Output is correct
74 Correct 351 ms 7512 KB Output is correct
75 Correct 388 ms 7516 KB Output is correct
76 Correct 341 ms 7716 KB Output is correct
77 Correct 348 ms 7724 KB Output is correct
78 Correct 368 ms 7680 KB Output is correct
79 Correct 339 ms 7676 KB Output is correct
80 Correct 370 ms 7516 KB Output is correct
81 Correct 363 ms 7684 KB Output is correct
82 Correct 342 ms 7684 KB Output is correct
83 Correct 389 ms 7760 KB Output is correct
84 Correct 365 ms 7660 KB Output is correct
85 Correct 400 ms 7512 KB Output is correct
86 Correct 381 ms 7644 KB Output is correct
87 Correct 378 ms 7640 KB Output is correct
88 Correct 364 ms 7584 KB Output is correct
89 Correct 384 ms 7516 KB Output is correct
90 Correct 381 ms 7512 KB Output is correct
91 Correct 372 ms 7760 KB Output is correct
92 Correct 390 ms 7516 KB Output is correct