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Submission #501945

# Submission time Handle Problem Language Result Execution time Memory
501945 2022-01-04T21:51:30 Z lorenzoferrari Mecho (IOI09_mecho) C++17
100 / 100
 245 ms 6356 KB 
#include <bits/stdc++.h>
using namespace std;
using LL = long long;

int32_t main() {
  int n, s;
  cin >> n >> s;
  vector<vector<char>> m(n, vector<char> (n));
  int xs, ys;
  int xe, ye;
  for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) {
    cin >> m[i][j];
    if (m[i][j] == 'M') xs = i, ys = j;
    if (m[i][j] == 'D') xe = i, ye = j;
  }
  queue<pair<int, int>> Q;
  vector<vector<int>> d(n, vector<int> (n, 1e9));
  for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) {
    if (m[i][j] == 'H') {
      d[i][j] = 0;
      Q.push({i, j});
    }
  }
  while (!Q.empty()) {
    auto [x, y] = Q.front();
    Q.pop();
    if (x     && (m[x-1][y  ] == 'G' || m[x-1][y  ] == 'M') && d[x-1][y  ] > d[x][y] + 1) d[x-1][y  ] = d[x][y] + 1, Q.push({x-1, y  });
    if (y     && (m[x  ][y-1] == 'G' || m[x  ][y-1] == 'M') && d[x  ][y-1] > d[x][y] + 1) d[x  ][y-1] = d[x][y] + 1, Q.push({x  , y-1});
    if (x<n-1 && (m[x+1][y  ] == 'G' || m[x+1][y  ] == 'M') && d[x+1][y  ] > d[x][y] + 1) d[x+1][y  ] = d[x][y] + 1, Q.push({x+1, y  });
    if (y<n-1 && (m[x  ][y+1] == 'G' || m[x  ][y+1] == 'M') && d[x  ][y+1] > d[x][y] + 1) d[x  ][y+1] = d[x][y] + 1, Q.push({x  , y+1});
  }
  auto psb = [&](int delay) {
    // bfs from mecho's location
    // it's possible iff dist_from_mecho[i][j]/s + delay < d[i][j]
    queue<pair<int, int>> Q;
    vector<vector<int>> dm(n, vector<int> (n, 1e9));
    Q.push({xs, ys});
    dm[xs][ys] = 0;
    while (!Q.empty()) {
      auto [x, y] = Q.front();
      Q.pop();
      if (delay + (dm[x][y]) / s >= d[x][y]) continue;
      if (x     && m[x-1][y  ] != 'T' && dm[x-1][y  ] > dm[x][y] + 1 && delay + (dm[x][y] + 1) / s < d[x-1][y  ]) dm[x-1][y  ] = dm[x][y] + 1, Q.push({x-1, y  });
      if (y     && m[x  ][y-1] != 'T' && dm[x  ][y-1] > dm[x][y] + 1 && delay + (dm[x][y] + 1) / s < d[x  ][y-1]) dm[x  ][y-1] = dm[x][y] + 1, Q.push({x  , y-1});
      if (x<n-1 && m[x+1][y  ] != 'T' && dm[x+1][y  ] > dm[x][y] + 1 && delay + (dm[x][y] + 1) / s < d[x+1][y  ]) dm[x+1][y  ] = dm[x][y] + 1, Q.push({x+1, y  });
      if (y<n-1 && m[x  ][y+1] != 'T' && dm[x  ][y+1] > dm[x][y] + 1 && delay + (dm[x][y] + 1) / s < d[x  ][y+1]) dm[x  ][y+1] = dm[x][y] + 1, Q.push({x  , y+1});
    }
    return dm[xe][ye] != 1e9;
  };
  int l = 0, r = n * n + 2;
  while (r - l > 1) {
    int mid = (l + r) / 2;
    if (psb(mid))
      l = mid;
    else
      r = mid;
  }
  cout << (psb(l) ? l : -1) << "\n";
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 204 KB Output is correct
4 Correct 0 ms 204 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 121 ms 6356 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
12 Correct 1 ms 332 KB Output is correct
13 Correct 1 ms 204 KB Output is correct
14 Correct 1 ms 332 KB Output is correct
15 Correct 1 ms 204 KB Output is correct
16 Correct 0 ms 204 KB Output is correct
17 Correct 0 ms 204 KB Output is correct
18 Correct 1 ms 204 KB Output is correct
19 Correct 0 ms 204 KB Output is correct
20 Correct 0 ms 204 KB Output is correct
21 Correct 0 ms 204 KB Output is correct
22 Correct 0 ms 204 KB Output is correct
23 Correct 1 ms 204 KB Output is correct
24 Correct 1 ms 204 KB Output is correct
25 Correct 1 ms 204 KB Output is correct
26 Correct 1 ms 204 KB Output is correct
27 Correct 1 ms 332 KB Output is correct
28 Correct 1 ms 332 KB Output is correct
29 Correct 1 ms 332 KB Output is correct
30 Correct 1 ms 332 KB Output is correct
31 Correct 1 ms 332 KB Output is correct
32 Correct 1 ms 332 KB Output is correct
33 Correct 11 ms 1400 KB Output is correct
34 Correct 12 ms 1396 KB Output is correct
35 Correct 26 ms 1412 KB Output is correct
36 Correct 15 ms 1804 KB Output is correct
37 Correct 15 ms 1740 KB Output is correct
38 Correct 34 ms 1620 KB Output is correct
39 Correct 19 ms 2104 KB Output is correct
40 Correct 20 ms 2152 KB Output is correct
41 Correct 48 ms 2108 KB Output is correct
42 Correct 23 ms 2532 KB Output is correct
43 Correct 28 ms 2716 KB Output is correct
44 Correct 57 ms 2584 KB Output is correct
45 Correct 33 ms 2988 KB Output is correct
46 Correct 28 ms 3068 KB Output is correct
47 Correct 66 ms 3044 KB Output is correct
48 Correct 33 ms 3548 KB Output is correct
49 Correct 34 ms 3568 KB Output is correct
50 Correct 97 ms 3540 KB Output is correct
51 Correct 42 ms 4068 KB Output is correct
52 Correct 40 ms 4104 KB Output is correct
53 Correct 96 ms 4064 KB Output is correct
54 Correct 46 ms 4732 KB Output is correct
55 Correct 46 ms 4736 KB Output is correct
56 Correct 150 ms 4708 KB Output is correct
57 Correct 63 ms 5368 KB Output is correct
58 Correct 59 ms 5368 KB Output is correct
59 Correct 136 ms 5352 KB Output is correct
60 Correct 60 ms 6056 KB Output is correct
61 Correct 60 ms 6048 KB Output is correct
62 Correct 162 ms 6036 KB Output is correct
63 Correct 148 ms 6188 KB Output is correct
64 Correct 245 ms 6076 KB Output is correct
65 Correct 196 ms 6020 KB Output is correct
66 Correct 162 ms 6084 KB Output is correct
67 Correct 150 ms 6036 KB Output is correct
68 Correct 86 ms 6056 KB Output is correct
69 Correct 97 ms 6032 KB Output is correct
70 Correct 90 ms 6060 KB Output is correct
71 Correct 79 ms 6060 KB Output is correct
72 Correct 72 ms 6068 KB Output is correct
73 Correct 71 ms 6092 KB Output is correct
74 Correct 99 ms 6072 KB Output is correct
75 Correct 126 ms 6088 KB Output is correct
76 Correct 107 ms 6072 KB Output is correct
77 Correct 122 ms 6076 KB Output is correct
78 Correct 106 ms 6080 KB Output is correct
79 Correct 81 ms 6076 KB Output is correct
80 Correct 93 ms 6048 KB Output is correct
81 Correct 131 ms 6060 KB Output is correct
82 Correct 101 ms 6052 KB Output is correct
83 Correct 106 ms 6060 KB Output is correct
84 Correct 108 ms 6084 KB Output is correct
85 Correct 120 ms 6080 KB Output is correct
86 Correct 122 ms 6076 KB Output is correct
87 Correct 116 ms 6080 KB Output is correct
88 Correct 110 ms 6052 KB Output is correct
89 Correct 151 ms 6036 KB Output is correct
90 Correct 123 ms 6068 KB Output is correct
91 Correct 116 ms 6060 KB Output is correct
92 Correct 118 ms 6196 KB Output is correct