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답안 #844001

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
844001 2023-09-04T21:37:21 Z cryan Mecho (IOI09_mecho) C++17
91 / 100
 1000 ms 8788 KB 
// oh, these hills, they burn so bright / oh, these hills, they bring me life
#include "bits/stdc++.h"
using namespace std;

using ll = long long;
#define all(x) begin(x), end(x)
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)(x.size())
#define inf 1000000010
#define linf 0x3f3f3f3f3f3f3f3f
#define mp make_pair
#define f first
#define s second
#define pi pair<int, int>
#ifdef LOCAL
#include "/mnt/c/yukon/pp.hpp"
#else
#define endl '\n'
#endif

struct Event {
	pi loc;
	int dist;
};
int grid[801][801];
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
int main() {
	cin.tie(0)->sync_with_stdio(0);

	int n;
	cin >> n;

	int S;
	cin >> S;

	vector<pi> hives;
	pi start, end;

	for (int i = 0; i < n; i++) {
		string st;
		cin >> st;

		for (int j = 0; j < n; j++) {
			if (st[j] == 'T')
				grid[i][j] = -1;
			else if (st[j] != 'D')
				grid[i][j] = 0;
			else
				grid[i][j] = 1, end = {i, j};

			if (st[j] == 'H') {
				hives.emplace_back(i, j);
			} else if (st[j] == 'M')
				start = {i, j};
		}
	}

	// let's get distance from bees first
	queue<Event> bfs;

	vector<vector<int>> dist_bees(n, vector<int>(n, inf));
	for (auto &[i, j] : hives) {
		bfs.push({{i, j}, 0});
		dist_bees[i][j] = 0;
	}
	while (!bfs.empty()) {
		auto [i, j] = bfs.front().loc;
		int dist = bfs.front().dist;
		bfs.pop();

		if (dist_bees[i][j] < dist)
			continue;

		for (int d = 0; d < 4; d++) {
			int new_i = i + dx[d], new_j = j + dy[d];

			if (new_i >= 0 && new_i < n && new_j >= 0 && new_j < n) {
				if (grid[new_i][new_j] != -1 && dist_bees[new_i][new_j] > dist + 1 && pi{new_i, new_j} != end) {
					dist_bees[new_i][new_j] = dist + 1;
					bfs.push({{new_i, new_j}, dist + 1});
				}
			}
		}
	}
	// for (int i = 0; i < n; i++) {
	// 	cout << dist_bees[i] << endl;
	// }

	// now mecho's turn
	bfs.push({{start.f, start.s}, 0});
	// just store distance w/o S factor
	vector<vector<int>> mecho_dist(n, vector<int>(n, -inf));
	mecho_dist[start.f][start.s] = dist_bees[start.f][start.s];

	while (sz(bfs)) {
		auto [i, j] = bfs.front().loc;
		int dist = bfs.front().dist;
		bfs.pop();
		if (mecho_dist[i][j] > dist_bees[i][j] - (dist) / S)
			continue;
		for (int d = 0; d < 4; d++) {
			int ni = i + dx[d], nj = j + dy[d];

			if (ni < 0 || ni >= n || nj < 0 || nj >= n)
				continue;

			int elapsed = (dist + 1) / S;
			// if (ni == 3 && nj == 3) {
			// 	cout << dist + 1 << ' ' << elapsed << ' ' << dist_bees[ni][nj] << endl;
			// }
			int lead = min(mecho_dist[i][j], dist_bees[ni][nj] - elapsed);
			if (grid[ni][nj] != -1 && mecho_dist[ni][nj] < lead && elapsed < dist_bees[ni][nj]) {
				mecho_dist[ni][nj] = lead;
				bfs.push({{ni, nj}, dist + 1});
			}
		}
	}
	// cout << "________" << endl;
	// for (int i = 0; i < n; i++) {
	// 	cout << mecho_dist[i] << endl;
	// }
	// cout << "________" << endl;
	// for (int i = 0; i < n; i++) {
	// 	cout << mecho_lead[i] << endl;
	// }

	int ans = -inf;
	for (int d = 0; d < 4; d++) {
		int ni = end.f + dx[d], nj = end.s + dy[d];

		if (ni < 0 || ni >= n || nj < 0 || nj >= n)
			continue;
		if (grid[ni][nj] == -1 || mecho_dist[ni][nj] == inf)
			continue;

		ans = max(ans, mecho_dist[ni][nj] - 1);
		// int elapsed = (mecho_dist[ni][nj] + S) / S;
		// ans = max(ans, dist_bees[ni][nj] - elapsed);
	}
	if (ans < 0) {
		cout << -1 << endl;
	} else {
		cout << ans << endl;
	}
}

// don't get stuck on one approach
// question bounds
// flesh out your approach before implementing o.o
// math it out
// ok well X is always possible, how about X + 1 (etc.)

Subtask #1
91.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 1 ms 500 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 1 ms 344 KB Output is correct
7 Correct 40 ms 8084 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 0 ms 356 KB Output is correct
10 Correct 0 ms 344 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 1 ms 2648 KB Output is correct
13 Correct 1 ms 600 KB Output is correct
14 Correct 1 ms 2648 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 0 ms 344 KB Output is correct
19 Correct 0 ms 348 KB Output is correct
20 Correct 0 ms 344 KB Output is correct
21 Correct 1 ms 344 KB Output is correct
22 Correct 0 ms 344 KB Output is correct
23 Correct 0 ms 604 KB Output is correct
24 Correct 0 ms 604 KB Output is correct
25 Correct 1 ms 2648 KB Output is correct
26 Correct 1 ms 2652 KB Output is correct
27 Correct 1 ms 2648 KB Output is correct
28 Correct 1 ms 2648 KB Output is correct
29 Correct 1 ms 2648 KB Output is correct
30 Correct 1 ms 2648 KB Output is correct
31 Correct 1 ms 2652 KB Output is correct
32 Correct 1 ms 2648 KB Output is correct
33 Correct 3 ms 3672 KB Output is correct
34 Correct 4 ms 3672 KB Output is correct
35 Correct 137 ms 3776 KB Output is correct
36 Correct 4 ms 3928 KB Output is correct
37 Correct 5 ms 3928 KB Output is correct
38 Correct 209 ms 4136 KB Output is correct
39 Correct 5 ms 4184 KB Output is correct
40 Correct 6 ms 4184 KB Output is correct
41 Correct 306 ms 4408 KB Output is correct
42 Correct 6 ms 4696 KB Output is correct
43 Correct 8 ms 4696 KB Output is correct
44 Correct 406 ms 4792 KB Output is correct
45 Correct 7 ms 5208 KB Output is correct
46 Correct 9 ms 4952 KB Output is correct
47 Correct 545 ms 5412 KB Output is correct
48 Correct 9 ms 5464 KB Output is correct
49 Correct 11 ms 5468 KB Output is correct
50 Correct 722 ms 5972 KB Output is correct
51 Correct 10 ms 5976 KB Output is correct
52 Correct 12 ms 5976 KB Output is correct
53 Correct 895 ms 6488 KB Output is correct
54 Correct 12 ms 6488 KB Output is correct
55 Correct 14 ms 6488 KB Output is correct
56 Execution timed out 1043 ms 7072 KB Time limit exceeded
57 Correct 13 ms 7052 KB Output is correct
58 Correct 16 ms 7256 KB Output is correct
59 Execution timed out 1022 ms 7632 KB Time limit exceeded
60 Correct 15 ms 8228 KB Output is correct
61 Correct 19 ms 8024 KB Output is correct
62 Execution timed out 1046 ms 8788 KB Time limit exceeded
63 Correct 34 ms 8024 KB Output is correct
64 Correct 38 ms 8024 KB Output is correct
65 Correct 35 ms 8024 KB Output is correct
66 Correct 34 ms 8024 KB Output is correct
67 Correct 34 ms 8024 KB Output is correct
68 Correct 32 ms 8016 KB Output is correct
69 Correct 30 ms 8024 KB Output is correct
70 Correct 27 ms 7880 KB Output is correct
71 Correct 26 ms 8024 KB Output is correct
72 Correct 28 ms 8024 KB Output is correct
73 Correct 26 ms 8128 KB Output is correct
74 Correct 57 ms 8112 KB Output is correct
75 Correct 27 ms 8024 KB Output is correct
76 Correct 27 ms 8024 KB Output is correct
77 Correct 28 ms 8024 KB Output is correct
78 Correct 28 ms 8024 KB Output is correct
79 Correct 301 ms 8324 KB Output is correct
80 Correct 45 ms 8024 KB Output is correct
81 Correct 28 ms 8024 KB Output is correct
82 Correct 88 ms 8028 KB Output is correct
83 Correct 30 ms 8016 KB Output is correct
84 Correct 80 ms 8116 KB Output is correct
85 Correct 143 ms 8140 KB Output is correct
86 Correct 187 ms 8260 KB Output is correct
87 Correct 47 ms 8024 KB Output is correct
88 Correct 117 ms 8292 KB Output is correct
89 Correct 344 ms 8276 KB Output is correct
90 Correct 33 ms 8024 KB Output is correct
91 Correct 52 ms 8024 KB Output is correct
92 Correct 35 ms 8024 KB Output is correct