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Submission #892752

# Submission time Handle Problem Language Result Execution time Memory
892752 2023-12-25T20:57:58 Z ilef Mecho (IOI09_mecho) C++14
100 / 100
 508 ms 7036 KB 
#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 800;
vector<string> field(MAX_N);
int n, s;
bool valid_sq(int x, int y) {
	return x >= 0 && x < n && y >= 0 && y < n &&
	       (field[x][y] == 'G' || field[x][y] == 'M');
}
bool mecho_reached(int mecho_dis, int bees_dis) {
	return mecho_dis / s < bees_dis;
}
int main() {
	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;
	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 dx[] = {-1, 0, 1, 0};
	int dy[] = {0, -1, 0, 1};
	int l = 0;
	int r = n * n;
	while (l <= r) {
		vector<vector<bool>> bees_visited(n, vector<bool>(n));
		vector<vector<bool>> mecho_visited(n, vector<bool>(n));
		vector<vector<int>> bees_time(n, vector<int>(n));
		vector<vector<int>> mecho_time(n, vector<int>(n));
		queue<pair<int, int>> q;
		int eating_time = (l + r) / 2;
		for (auto i : hives) {
			q.push({i.first, i.second});
			bees_visited[i.first][i.second] = true;
		}
		while (!q.empty()) {
			int x = q.front().first, y = q.front().second;
			q.pop();
			for (int i = 0; i < 4; i++) {
				int nx = x + dx[i], ny = y + dy[i];
				if (valid_sq(nx, ny) && !bees_visited[nx][ny]) {
					bees_time[nx][ny] = bees_time[x][y] + 1;
					q.push({nx, ny});
					bees_visited[nx][ny] = true;
				}
			}
		}
		q.push({mechox, mechoy});
		mecho_visited[mechox][mechoy] = true;
		if (bees_time[mechox][mechoy] <= eating_time) { q.pop(); }
		while (!q.empty()) {
			int x = q.front().first, y = q.front().second;
			q.pop();
			for (int i = 0; i < 4; i++) {
				int nx = x + dx[i], ny = y + dy[i];
				if (valid_sq(nx, ny) && !mecho_visited[nx][ny] &&
				    mecho_reached(mecho_time[x][y] + 1,
				                  bees_time[nx][ny] - eating_time)) {
					mecho_visited[nx][ny] = true;
					q.push({nx, ny});
					mecho_time[nx][ny] = mecho_time[x][y] + 1;
				}
			}
		}
		bool 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) &&
			    mecho_reached(mecho_time[nx][ny],
			                  bees_time[nx][ny] - eating_time) &&
			    mecho_visited[nx][ny]) {
				reached = true;
			}
		}
		if (reached) {
			l = eating_time + 1;
		} else {
			r = eating_time - 1;
		}
	}
	cout << l - 1 << '\n';
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:59:31: warning: 'mechoy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   59 |   mecho_visited[mechox][mechoy] = true;
      |                               ^
mecho.cpp:59:23: warning: 'mechox' may be used uninitialized in this function [-Wmaybe-uninitialized]
   59 |   mecho_visited[mechox][mechoy] = true;
      |                       ^
mecho.cpp:77:29: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   77 |    int nx = home_x + dx[i], ny = home_y + dy[i];
      |                             ^~
mecho.cpp:77:8: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   77 |    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 0 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 404 ms 6836 KB Output is correct
8 Correct 1 ms 344 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 2 ms 344 KB Output is correct
15 Correct 0 ms 344 KB Output is correct
16 Correct 0 ms 344 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 1 ms 424 KB Output is correct
19 Correct 1 ms 348 KB Output is correct
20 Correct 1 ms 348 KB Output is correct
21 Correct 1 ms 348 KB Output is correct
22 Correct 1 ms 348 KB Output is correct
23 Correct 1 ms 348 KB Output is correct
24 Correct 1 ms 348 KB Output is correct
25 Correct 1 ms 348 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 1 ms 348 KB Output is correct
28 Correct 1 ms 348 KB Output is correct
29 Correct 1 ms 388 KB Output is correct
30 Correct 1 ms 348 KB Output is correct
31 Correct 1 ms 348 KB Output is correct
32 Correct 2 ms 348 KB Output is correct
33 Correct 32 ms 1640 KB Output is correct
34 Correct 30 ms 1640 KB Output is correct
35 Correct 60 ms 1628 KB Output is correct
36 Correct 41 ms 2196 KB Output is correct
37 Correct 43 ms 2008 KB Output is correct
38 Correct 80 ms 2276 KB Output is correct
39 Correct 52 ms 2400 KB Output is correct
40 Correct 51 ms 2408 KB Output is correct
41 Correct 105 ms 2396 KB Output is correct
42 Correct 72 ms 3028 KB Output is correct
43 Correct 65 ms 3032 KB Output is correct
44 Correct 142 ms 2908 KB Output is correct
45 Correct 85 ms 3516 KB Output is correct
46 Correct 77 ms 3520 KB Output is correct
47 Correct 182 ms 3512 KB Output is correct
48 Correct 101 ms 4316 KB Output is correct
49 Correct 95 ms 4048 KB Output is correct
50 Correct 184 ms 3928 KB Output is correct
51 Correct 121 ms 4592 KB Output is correct
52 Correct 127 ms 4884 KB Output is correct
53 Correct 240 ms 4584 KB Output is correct
54 Correct 142 ms 5188 KB Output is correct
55 Correct 146 ms 5480 KB Output is correct
56 Correct 277 ms 5188 KB Output is correct
57 Correct 157 ms 5872 KB Output is correct
58 Correct 156 ms 5912 KB Output is correct
59 Correct 315 ms 5836 KB Output is correct
60 Correct 189 ms 6548 KB Output is correct
61 Correct 170 ms 6676 KB Output is correct
62 Correct 351 ms 6516 KB Output is correct
63 Correct 423 ms 6536 KB Output is correct
64 Correct 508 ms 6524 KB Output is correct
65 Correct 502 ms 6700 KB Output is correct
66 Correct 467 ms 6892 KB Output is correct
67 Correct 448 ms 6740 KB Output is correct
68 Correct 397 ms 6736 KB Output is correct
69 Correct 407 ms 6492 KB Output is correct
70 Correct 378 ms 6552 KB Output is correct
71 Correct 394 ms 6548 KB Output is correct
72 Correct 375 ms 6548 KB Output is correct
73 Correct 396 ms 6744 KB Output is correct
74 Correct 402 ms 6820 KB Output is correct
75 Correct 444 ms 6824 KB Output is correct
76 Correct 398 ms 6844 KB Output is correct
77 Correct 399 ms 6900 KB Output is correct
78 Correct 422 ms 6784 KB Output is correct
79 Correct 375 ms 6952 KB Output is correct
80 Correct 376 ms 6744 KB Output is correct
81 Correct 403 ms 7036 KB Output is correct
82 Correct 388 ms 6748 KB Output is correct
83 Correct 415 ms 7004 KB Output is correct
84 Correct 400 ms 6748 KB Output is correct
85 Correct 432 ms 6748 KB Output is correct
86 Correct 417 ms 6744 KB Output is correct
87 Correct 402 ms 6748 KB Output is correct
88 Correct 399 ms 6492 KB Output is correct
89 Correct 400 ms 6488 KB Output is correct
90 Correct 404 ms 6740 KB Output is correct
91 Correct 410 ms 6492 KB Output is correct
92 Correct 431 ms 6936 KB Output is correct