oj.uz

Submission #844007

# Submission time Handle Problem Language Result Execution time Memory
844007 2023-09-04T21:47:05 Z cryan Mecho (IOI09_mecho) C++17
94 / 100
 1000 ms 8676 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

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
struct Event {
	pi loc;
	int dist;
};
int grid[801][801], dist_bees[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;
	memset(dist_bees, 0x3f, sizeof dist_bees);

	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] == 0 && dist_bees[new_i][new_j] > dist + 1) {
					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;
		int elapsed = (dist + 1) / S;
		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;

			// 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
94.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4952 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4700 KB Output is correct
7 Correct 33 ms 7976 KB Output is correct
8 Correct 1 ms 4700 KB Output is correct
9 Correct 1 ms 4700 KB Output is correct
10 Correct 1 ms 4696 KB Output is correct
11 Correct 1 ms 4696 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 1 ms 4700 KB Output is correct
14 Correct 1 ms 4728 KB Output is correct
15 Correct 1 ms 4700 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct
17 Correct 1 ms 4700 KB Output is correct
18 Correct 1 ms 4700 KB Output is correct
19 Correct 1 ms 4700 KB Output is correct
20 Correct 1 ms 4700 KB Output is correct
21 Correct 1 ms 4700 KB Output is correct
22 Correct 1 ms 4696 KB Output is correct
23 Correct 1 ms 4700 KB Output is correct
24 Correct 1 ms 4700 KB Output is correct
25 Correct 1 ms 4700 KB Output is correct
26 Correct 1 ms 4740 KB Output is correct
27 Correct 1 ms 4700 KB Output is correct
28 Correct 1 ms 4700 KB Output is correct
29 Correct 1 ms 4568 KB Output is correct
30 Correct 1 ms 4700 KB Output is correct
31 Correct 1 ms 4700 KB Output is correct
32 Correct 1 ms 4700 KB Output is correct
33 Correct 2 ms 5212 KB Output is correct
34 Correct 3 ms 5212 KB Output is correct
35 Correct 99 ms 5340 KB Output is correct
36 Correct 3 ms 5212 KB Output is correct
37 Correct 4 ms 5212 KB Output is correct
38 Correct 151 ms 5500 KB Output is correct
39 Correct 4 ms 5464 KB Output is correct
40 Correct 5 ms 5468 KB Output is correct
41 Correct 218 ms 5752 KB Output is correct
42 Correct 4 ms 5724 KB Output is correct
43 Correct 6 ms 5724 KB Output is correct
44 Correct 306 ms 6108 KB Output is correct
45 Correct 5 ms 5724 KB Output is correct
46 Correct 8 ms 5720 KB Output is correct
47 Correct 392 ms 6248 KB Output is correct
48 Correct 6 ms 6232 KB Output is correct
49 Correct 7 ms 6488 KB Output is correct
50 Correct 537 ms 6612 KB Output is correct
51 Correct 7 ms 6492 KB Output is correct
52 Correct 9 ms 6492 KB Output is correct
53 Correct 671 ms 7140 KB Output is correct
54 Correct 8 ms 7004 KB Output is correct
55 Correct 11 ms 7136 KB Output is correct
56 Correct 824 ms 7636 KB Output is correct
57 Correct 9 ms 7512 KB Output is correct
58 Correct 11 ms 7516 KB Output is correct
59 Execution timed out 1018 ms 8216 KB Time limit exceeded
60 Correct 11 ms 8028 KB Output is correct
61 Correct 12 ms 8024 KB Output is correct
62 Execution timed out 1055 ms 8676 KB Time limit exceeded
63 Correct 28 ms 8028 KB Output is correct
64 Correct 30 ms 8024 KB Output is correct
65 Correct 29 ms 8024 KB Output is correct
66 Correct 29 ms 8028 KB Output is correct
67 Correct 23 ms 8028 KB Output is correct
68 Correct 21 ms 7900 KB Output is correct
69 Correct 22 ms 8028 KB Output is correct
70 Correct 21 ms 8024 KB Output is correct
71 Correct 20 ms 7856 KB Output is correct
72 Correct 23 ms 8028 KB Output is correct
73 Correct 18 ms 8028 KB Output is correct
74 Correct 40 ms 8028 KB Output is correct
75 Correct 18 ms 8028 KB Output is correct
76 Correct 22 ms 7996 KB Output is correct
77 Correct 19 ms 8028 KB Output is correct
78 Correct 19 ms 8028 KB Output is correct
79 Correct 203 ms 8216 KB Output is correct
80 Correct 36 ms 8028 KB Output is correct
81 Correct 20 ms 8028 KB Output is correct
82 Correct 60 ms 8136 KB Output is correct
83 Correct 22 ms 8028 KB Output is correct
84 Correct 63 ms 8276 KB Output is correct
85 Correct 100 ms 8148 KB Output is correct
86 Correct 129 ms 8200 KB Output is correct
87 Correct 33 ms 8024 KB Output is correct
88 Correct 73 ms 8152 KB Output is correct
89 Correct 258 ms 8228 KB Output is correct
90 Correct 24 ms 8028 KB Output is correct
91 Correct 38 ms 8056 KB Output is correct
92 Correct 26 ms 8024 KB Output is correct