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Submission #264730

# Submission time Handle Problem Language Result Execution time Memory
264730 2020-08-14T08:37:31 Z WLZ Mecho (IOI09_mecho) C++17
100 / 100
 945 ms 6408 KB 
#include <bits/stdc++.h>
using namespace std;

const int INF = 0x3f3f3f3f;
const vector<int> dx = {0, 0, -1, 1};
const vector<int> dy = {1, -1, 0, 0};

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, s;
  cin >> n >> s;
  vector<string> grid(n);
  queue< pair<int, int> > q;
  vector< vector<int> > dist1(n, vector<int>(n, -1));
  int mr, mc, dr, dc;
  for (int i = 0; i < n; i++) {
    cin >> grid[i];
    for (int j = 0; j < n; j++) {
      if (grid[i][j] == 'M') {
        mr = i; mc = j;
      } else if (grid[i][j] == 'H') {
        q.push({i, j});
        dist1[i][j] = 0;
      } else if (grid[i][j] == 'D') {
        dr = i; dc = j;
      }
    }
  }
  while (!q.empty()) {
    int r = q.front().first, c = q.front().second;
    q.pop();
    for (int k = 0; k < 4; k++) {
      int nr = r + dx[k], nc = c + dy[k];
      if (nr < 0 || nr >= n || nc < 0 || nc >= n || grid[nr][nc] == 'T' || dist1[nr][nc] != -1 || grid[nr][nc] == 'D') {
        continue;
      }
      dist1[nr][nc] = dist1[r][c] + s;
      q.push({nr, nc});
    }
  }
  int lo = 0, hi = n * n, ans = -1;
  for (int i = 0; i < 50; i++) {
    int mid = (lo + hi) / 2;
    //cout << mid << endl;
    vector< vector<int> > dist2(n, vector<int>(n, INF));
    dist2[mr][mc] = s * mid;
    if (dist2[mr][mc] >= dist1[mr][mc]) {
      hi = mid - 1;
      continue;
    }
    q.push({mr, mc});
    while (!q.empty()) {
      int r = q.front().first, c = q.front().second;
      //cout << r << ' ' << c << endl;
      q.pop();
      for (int k = 0; k < 4; k++) {
        int nr = r + dx[k], nc = c + dy[k];
        if (nr < 0 || nr >= n || nc < 0 || nc >= n || dist2[r][c] + 1 >= dist2[nr][nc] || ((nr != dr || nc != dc) && dist2[r][c] + 1 >= dist1[nr][nc]) || grid[nr][nc] == 'T') {
          continue;
        }
        dist2[nr][nc] = dist2[r][c] + 1;
        q.push({nr, nc});
      }
    }
    if (dist2[dr][dc] < INF) {
      ans = mid;
      lo = mid + 1;
    } else {
      hi = mid - 1;
    }
  }
  cout << ans << '\n';
  return 0;
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:47:17: warning: 'mc' may be used uninitialized in this function [-Wmaybe-uninitialized]
   47 |     dist2[mr][mc] = s * mid;
      |                 ^
mecho.cpp:47:13: warning: 'mr' may be used uninitialized in this function [-Wmaybe-uninitialized]
   47 |     dist2[mr][mc] = s * mid;
      |             ^
mecho.cpp:66:21: warning: 'dc' may be used uninitialized in this function [-Wmaybe-uninitialized]
   66 |     if (dist2[dr][dc] < INF) {
      |                     ^
mecho.cpp:66:17: warning: 'dr' may be used uninitialized in this function [-Wmaybe-uninitialized]
   66 |     if (dist2[dr][dc] < INF) {
      |                 ^

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 288 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 535 ms 6252 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 0 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 3 ms 384 KB Output is correct
14 Correct 3 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 1 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 1 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 1 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 1 ms 384 KB Output is correct
29 Correct 1 ms 384 KB Output is correct
30 Correct 1 ms 384 KB Output is correct
31 Correct 1 ms 384 KB Output is correct
32 Correct 1 ms 384 KB Output is correct
33 Correct 13 ms 1508 KB Output is correct
34 Correct 15 ms 1688 KB Output is correct
35 Correct 138 ms 1508 KB Output is correct
36 Correct 18 ms 1848 KB Output is correct
37 Correct 22 ms 2016 KB Output is correct
38 Correct 182 ms 1844 KB Output is correct
39 Correct 23 ms 2392 KB Output is correct
40 Correct 27 ms 2300 KB Output is correct
41 Correct 234 ms 2224 KB Output is correct
42 Correct 29 ms 2840 KB Output is correct
43 Correct 32 ms 2656 KB Output is correct
44 Correct 299 ms 2824 KB Output is correct
45 Correct 33 ms 3104 KB Output is correct
46 Correct 36 ms 3296 KB Output is correct
47 Correct 351 ms 3160 KB Output is correct
48 Correct 40 ms 3776 KB Output is correct
49 Correct 41 ms 3640 KB Output is correct
50 Correct 447 ms 3648 KB Output is correct
51 Correct 49 ms 4316 KB Output is correct
52 Correct 51 ms 4312 KB Output is correct
53 Correct 520 ms 4220 KB Output is correct
54 Correct 58 ms 4912 KB Output is correct
55 Correct 64 ms 4816 KB Output is correct
56 Correct 674 ms 4944 KB Output is correct
57 Correct 68 ms 5556 KB Output is correct
58 Correct 70 ms 5608 KB Output is correct
59 Correct 759 ms 5548 KB Output is correct
60 Correct 78 ms 6212 KB Output is correct
61 Correct 79 ms 6224 KB Output is correct
62 Correct 850 ms 6400 KB Output is correct
63 Correct 766 ms 6384 KB Output is correct
64 Correct 945 ms 6260 KB Output is correct
65 Correct 904 ms 6204 KB Output is correct
66 Correct 755 ms 6212 KB Output is correct
67 Correct 683 ms 6152 KB Output is correct
68 Correct 331 ms 6184 KB Output is correct
69 Correct 376 ms 6184 KB Output is correct
70 Correct 258 ms 6252 KB Output is correct
71 Correct 267 ms 6200 KB Output is correct
72 Correct 101 ms 6232 KB Output is correct
73 Correct 419 ms 6380 KB Output is correct
74 Correct 315 ms 6224 KB Output is correct
75 Correct 390 ms 6224 KB Output is correct
76 Correct 342 ms 6268 KB Output is correct
77 Correct 337 ms 6320 KB Output is correct
78 Correct 431 ms 6272 KB Output is correct
79 Correct 280 ms 6216 KB Output is correct
80 Correct 322 ms 6204 KB Output is correct
81 Correct 376 ms 6408 KB Output is correct
82 Correct 303 ms 6196 KB Output is correct
83 Correct 468 ms 6348 KB Output is correct
84 Correct 387 ms 6232 KB Output is correct
85 Correct 433 ms 6308 KB Output is correct
86 Correct 476 ms 6180 KB Output is correct
87 Correct 429 ms 6228 KB Output is correct
88 Correct 588 ms 6240 KB Output is correct
89 Correct 528 ms 6172 KB Output is correct
90 Correct 522 ms 6240 KB Output is correct
91 Correct 561 ms 6384 KB Output is correct
92 Correct 516 ms 6260 KB Output is correct