답안 #716336

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
716336	2023-03-29T17:22:09 Z	yashsingh	Mecho (IOI09_mecho)	C++17	95 / 100	197 ms	6076 KB

mecho

#include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> pii;

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n, s;
	cin >> n >> s;

	vector<vector<char>> grid(n, vector<char>(n));
	
	pii start, end;
	for (int i{0}; i < n; ++i) {
		for (int j{0}; j < n; ++j) {
			cin >> grid[i][j];
			if (grid[i][j] == 'M') start = {i,j};
			else if (grid[i][j] == 'D') end = {i,j};
		}
	}

	queue<pair<int,int>> q;
	vector<vector<int>> pollu(n, vector<int>(n, INT_MAX));
	for (int i{0}; i < n; ++i) {
		for (int j{0}; j < n; ++j) {
			if (grid[i][j] == 'H') {
				pollu[i][j] = 0;
				q.push({i, j});
			}
		}
	}

	// precompute distance to pollinate all regions
	int dx[4] {-1, 1, 0, 0};
	int dy[4] {0, 0, 1, -1};
	while (q.size()) {
		int x = q.front().first;
		int y = q.front().second;
		q.pop();
		for (int i{0}; i < 4; ++i) {
			if (x + dx[i] < 0 || x + dx[i] >= n || y + dy[i] < 0 || y + dy[i] >= n || grid[x + dx[i]][y + dy[i]] == 'T') {
				continue;
			}
			if (pollu[x][y] + 1 < pollu[x + dx[i]][y + dy[i]]) {
				pollu[x + dx[i]][y + dy[i]] = pollu[x][y] + 1;
				q.push({x + dx[i], y + dy[i]});
			}
		}
	}

	// for (int i{0}; i < n; ++i) {
	// 	for (int j{0}; j < n; ++j) {
	// 		if (pollu[i][j] == INT_MAX) {
	// 			cout << '-' << ' ';
	// 			continue;
	// 		}
	// 		cout << pollu[i][j] << ' ';
	// 	}
	// 	cout << '\n';
	// }

	// we can tell by construction that any adjacent cell will have either +1 or -1, we want to move on +1 route
	// similarly we can tell that a movement of s cells is +[0,s]
	// we want to find a maximum min over all segments of size s
	// we can start by precomputing the distance to each cell from M

	vector<vector<int>> dist(n, vector<int>(n, INT_MAX));

	// implement binary search with bfs
	// can't precompute distances, they are dependent on bee timings
	int l{0}, r{n*n}, ans{-1};
	while (l <= r) {
		int mid{(l+r)/2};
		q.push(start);
		for (int i{0}; i < n; ++i) {
			for (int j{0}; j < n; ++j) {
				dist[i][j] = INT_MAX;
			}
		}
		dist[start.first][start.second] = 0;
		while (q.size()) {
			int x = q.front().first;
			int y = q.front().second;
			q.pop();
			for (int i{0}; i < 4; ++i) {
				if (x + dx[i] < 0 || x + dx[i] >= n || y + dy[i] < 0 || y + dy[i] >= n) continue;
				if (grid[x + dx[i]][y + dy[i]] == 'T') continue;
				if (pollu[x][y]-mid > (dist[x][y])/s && dist[x][y] + 1 < dist[x + dx[i]][y + dy[i]]) {
					dist[x + dx[i]][y + dy[i]] = dist[x][y] + 1;
					q.push({x + dx[i], y + dy[i]});
				}
			}
		}
		// cout << mid << '\n';
		// for (int i{0}; i < n; ++i) {
		// 	for (int j{0}; j < n; ++j) {
		// 		if (dist[i][j] == INT_MAX) {
		// 			cout << '-' << ' ';
		// 			continue;
		// 		}
		// 		cout << dist[i][j] << ' ';
		// 	}
		// 	cout << '\n';
		// }
		if (dist[end.first][end.second] == INT_MAX) {
			r = mid-1;
		} else {
			l = mid+1;
			ans = mid;
		}
	}

	cout << ans << "\n";

  return 0;
}

Subtask #1

95.0 / 100.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	1 ms	212 KB	Output is correct
3	Correct	1 ms	212 KB	Output is correct
4	Correct	0 ms	212 KB	Output is correct
5	Correct	1 ms	212 KB	Output is correct
6	Correct	1 ms	300 KB	Output is correct
7	Correct	97 ms	6056 KB	Output is correct
8	Correct	0 ms	212 KB	Output is correct
9	Correct	1 ms	212 KB	Output is correct
10	Correct	1 ms	212 KB	Output is correct
11	Correct	0 ms	212 KB	Output is correct
12	Incorrect	1 ms	340 KB	Output isn't correct
13	Correct	1 ms	340 KB	Output is correct
14	Correct	1 ms	340 KB	Output is correct
15	Correct	1 ms	212 KB	Output is correct
16	Correct	1 ms	212 KB	Output is correct
17	Correct	1 ms	212 KB	Output is correct
18	Correct	0 ms	212 KB	Output is correct
19	Correct	0 ms	212 KB	Output is correct
20	Correct	1 ms	212 KB	Output is correct
21	Correct	1 ms	212 KB	Output is correct
22	Correct	1 ms	212 KB	Output is correct
23	Correct	1 ms	340 KB	Output is correct
24	Correct	0 ms	340 KB	Output is correct
25	Correct	1 ms	240 KB	Output is correct
26	Correct	1 ms	340 KB	Output is correct
27	Correct	1 ms	340 KB	Output is correct
28	Correct	1 ms	340 KB	Output is correct
29	Correct	1 ms	340 KB	Output is correct
30	Correct	1 ms	340 KB	Output is correct
31	Correct	1 ms	340 KB	Output is correct
32	Correct	1 ms	340 KB	Output is correct
33	Correct	5 ms	1364 KB	Output is correct
34	Correct	6 ms	1324 KB	Output is correct
35	Correct	23 ms	1444 KB	Output is correct
36	Correct	7 ms	1648 KB	Output is correct
37	Correct	7 ms	1748 KB	Output is correct
38	Correct	42 ms	1764 KB	Output is correct
39	Correct	9 ms	2148 KB	Output is correct
40	Correct	11 ms	2132 KB	Output is correct
41	Correct	44 ms	2136 KB	Output is correct
42	Correct	10 ms	2588 KB	Output is correct
43	Correct	15 ms	2504 KB	Output is correct
44	Correct	48 ms	2480 KB	Output is correct
45	Correct	12 ms	3028 KB	Output is correct
46	Correct	13 ms	3028 KB	Output is correct
47	Correct	61 ms	3024 KB	Output is correct
48	Correct	16 ms	3560 KB	Output is correct
49	Correct	17 ms	3540 KB	Output is correct
50	Correct	70 ms	3548 KB	Output is correct
51	Correct	18 ms	4052 KB	Output is correct
52	Correct	18 ms	4100 KB	Output is correct
53	Correct	85 ms	4108 KB	Output is correct
54	Correct	21 ms	4700 KB	Output is correct
55	Correct	23 ms	4692 KB	Output is correct
56	Correct	100 ms	4744 KB	Output is correct
57	Correct	23 ms	5300 KB	Output is correct
58	Correct	32 ms	5304 KB	Output is correct
59	Correct	112 ms	5348 KB	Output is correct
60	Correct	29 ms	5936 KB	Output is correct
61	Correct	28 ms	5968 KB	Output is correct
62	Correct	128 ms	5972 KB	Output is correct
63	Correct	105 ms	5964 KB	Output is correct
64	Correct	197 ms	6036 KB	Output is correct
65	Correct	157 ms	6040 KB	Output is correct
66	Correct	144 ms	6036 KB	Output is correct
67	Correct	119 ms	6076 KB	Output is correct
68	Correct	67 ms	5964 KB	Output is correct
69	Correct	51 ms	5964 KB	Output is correct
70	Correct	43 ms	5956 KB	Output is correct
71	Correct	60 ms	5960 KB	Output is correct
72	Correct	37 ms	5960 KB	Output is correct
73	Correct	36 ms	5968 KB	Output is correct
74	Correct	65 ms	6072 KB	Output is correct
75	Correct	82 ms	5960 KB	Output is correct
76	Correct	69 ms	5976 KB	Output is correct
77	Correct	71 ms	5964 KB	Output is correct
78	Correct	81 ms	5964 KB	Output is correct
79	Correct	54 ms	6072 KB	Output is correct
80	Correct	71 ms	6068 KB	Output is correct
81	Correct	85 ms	6056 KB	Output is correct
82	Correct	66 ms	6076 KB	Output is correct
83	Correct	85 ms	6068 KB	Output is correct
84	Correct	75 ms	6036 KB	Output is correct
85	Correct	95 ms	6028 KB	Output is correct
86	Correct	108 ms	6060 KB	Output is correct
87	Correct	84 ms	5964 KB	Output is correct
88	Correct	85 ms	6060 KB	Output is correct
89	Correct	83 ms	6064 KB	Output is correct
90	Correct	110 ms	5972 KB	Output is correct
91	Correct	97 ms	6064 KB	Output is correct
92	Correct	99 ms	5968 KB	Output is correct