oj.uz

Submission #621375

# Submission time Handle Problem Language Result Execution time Memory
621375 2022-08-03T18:09:02 Z abcisosm5 Mecho (IOI09_mecho) C++17
38 / 100
 697 ms 3008 KB 
#include <bits/stdc++.h>
using namespace std;
#define pi pair<int, int>
#define f first
#define s second

int N, S;
const int MN = 800;
char grid[MN][MN] = {{}};
vector<pi> hives;
pi M; pi D;
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

void movebees(queue<pi> (&b), char (&v)[MN][MN], int t){
	for(int i = 0; i < t; i++){
		queue<pi> nextb;
		while(!b.empty()){
			pi p = b.front(); b.pop();
			for(int d = 0; d < 4; d++){
				int nx = p.f + dx[d]; int ny = p.s + dy[d];
				if(nx < 0 || nx >= N || ny < 0 || ny >= N) continue;
				if(v[nx][ny] != 'B' && grid[nx][ny] == 'G'){
					v[nx][ny] = 'B';
					nextb.push({nx, ny});
				}
			}
		}
		b = nextb;
	}
}

bool movemecho(queue<pi> (&m), char (&v)[MN][MN]){
	for(int i = 0; i < S; i++){
		queue<pi> nextm;
		while(!m.empty()){
			pi p = m.front(); m.pop();
			for(int d = 0; d < 4; d++){
				int nx = p.f + dx[d]; int ny = p.s + dy[d];
				if(nx < 0 || nx >= N || ny < 0 || ny >= N) continue;
				if(!v[nx][ny] && grid[nx][ny] != 'T'){
					if(grid[nx][ny] == 'D') return true;
					v[nx][ny] = 'M';
					nextm.push({nx, ny});
				}
			}
		}
		m = nextm;
	}
	return false;
}

bool works(int t){ //O(N^2)
	char visited[MN][MN] = {{}};
	queue<pi> bees;
	for(pi p : hives){
		bees.push(p);
		visited[p.first][p.second] = 'B'; 
	}
	movebees(bees, visited, t);

	queue<pi> mecho; mecho.push(M); visited[M.f][M.s] = 'M';
	
	for(int i = 0; i < N*N/2; i++){
		//first, move mecho S steps
		if(mecho.empty()) break;
		bool success = movemecho(mecho, visited);
		if(success) return true;

		//then, move bees 1 step
		movebees(bees, visited, 1);
	}

	return false;
}

int main(){
	cin.tie(0)->sync_with_stdio(0);

	cin >> N >> S;

	for(int i = 0; i < N; i++){
		for(int j = 0; j < N; j++){
			cin >> grid[i][j];

			if(grid[i][j] == 'M') M = {i, j};
			if(grid[i][j] == 'D') D = {i, j};
			if(grid[i][j] == 'H') hives.push_back({i,j});
		}
	}

	int lo = -1; int hi = N*N/2; //amount of head start to bees

	while(lo < hi){ // in total, O(N^2 log N)
		int mid = lo + (hi - lo + 1) / 2;
		if(works(mid)){
			lo = mid;
		} else {
			hi = mid - 1;
		}
	}

	cout << lo;

	return 0;
}

Subtask #1
38.0 / 100.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 848 KB Output isn't correct
2 Incorrect 1 ms 844 KB Output isn't correct
3 Incorrect 1 ms 852 KB Output isn't correct
4 Incorrect 1 ms 852 KB Output isn't correct
5 Correct 1 ms 852 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 289 ms 2416 KB Output is correct
8 Incorrect 1 ms 852 KB Output isn't correct
9 Correct 1 ms 852 KB Output is correct
10 Correct 1 ms 852 KB Output is correct
11 Correct 1 ms 852 KB Output is correct
12 Incorrect 3 ms 980 KB Output isn't correct
13 Incorrect 2 ms 980 KB Output isn't correct
14 Correct 2 ms 980 KB Output is correct
15 Incorrect 1 ms 980 KB Output isn't correct
16 Correct 1 ms 980 KB Output is correct
17 Incorrect 1 ms 980 KB Output isn't correct
18 Correct 1 ms 852 KB Output is correct
19 Incorrect 1 ms 980 KB Output isn't correct
20 Correct 2 ms 980 KB Output is correct
21 Incorrect 2 ms 980 KB Output isn't correct
22 Correct 2 ms 980 KB Output is correct
23 Incorrect 2 ms 980 KB Output isn't correct
24 Correct 2 ms 996 KB Output is correct
25 Incorrect 5 ms 1004 KB Output isn't correct
26 Correct 2 ms 980 KB Output is correct
27 Incorrect 3 ms 984 KB Output isn't correct
28 Correct 2 ms 980 KB Output is correct
29 Incorrect 3 ms 972 KB Output isn't correct
30 Correct 3 ms 980 KB Output is correct
31 Incorrect 4 ms 980 KB Output isn't correct
32 Correct 5 ms 980 KB Output is correct
33 Incorrect 74 ms 1236 KB Output isn't correct
34 Correct 49 ms 1328 KB Output is correct
35 Correct 37 ms 1236 KB Output is correct
36 Incorrect 112 ms 1412 KB Output isn't correct
37 Correct 107 ms 1424 KB Output is correct
38 Correct 47 ms 1352 KB Output is correct
39 Incorrect 132 ms 1488 KB Output isn't correct
40 Correct 86 ms 1496 KB Output is correct
41 Correct 81 ms 1480 KB Output is correct
42 Incorrect 171 ms 1568 KB Output isn't correct
43 Correct 112 ms 1580 KB Output is correct
44 Correct 79 ms 1496 KB Output is correct
45 Incorrect 288 ms 1668 KB Output isn't correct
46 Correct 145 ms 1664 KB Output is correct
47 Correct 118 ms 1672 KB Output is correct
48 Incorrect 343 ms 1760 KB Output isn't correct
49 Correct 171 ms 1788 KB Output is correct
50 Correct 105 ms 1748 KB Output is correct
51 Incorrect 345 ms 1860 KB Output isn't correct
52 Correct 197 ms 1860 KB Output is correct
53 Correct 136 ms 1856 KB Output is correct
54 Incorrect 331 ms 1972 KB Output isn't correct
55 Correct 205 ms 2016 KB Output is correct
56 Correct 156 ms 1984 KB Output is correct
57 Incorrect 379 ms 2072 KB Output isn't correct
58 Correct 267 ms 2064 KB Output is correct
59 Correct 173 ms 2004 KB Output is correct
60 Incorrect 455 ms 2208 KB Output isn't correct
61 Correct 302 ms 2188 KB Output is correct
62 Correct 212 ms 2200 KB Output is correct
63 Correct 295 ms 2132 KB Output is correct
64 Correct 287 ms 2200 KB Output is correct
65 Correct 268 ms 2200 KB Output is correct
66 Incorrect 301 ms 2196 KB Output isn't correct
67 Correct 274 ms 2200 KB Output is correct
68 Correct 285 ms 2260 KB Output is correct
69 Correct 252 ms 2260 KB Output is correct
70 Correct 287 ms 2260 KB Output is correct
71 Correct 321 ms 2260 KB Output is correct
72 Incorrect 697 ms 2252 KB Output isn't correct
73 Incorrect 314 ms 2764 KB Output isn't correct
74 Correct 289 ms 3008 KB Output is correct
75 Correct 312 ms 2772 KB Output is correct
76 Correct 307 ms 2772 KB Output is correct
77 Correct 312 ms 2920 KB Output is correct
78 Correct 319 ms 2700 KB Output is correct
79 Correct 358 ms 2704 KB Output is correct
80 Correct 325 ms 2704 KB Output is correct
81 Correct 328 ms 2804 KB Output is correct
82 Correct 351 ms 2748 KB Output is correct
83 Correct 347 ms 2624 KB Output is correct
84 Correct 308 ms 2620 KB Output is correct
85 Correct 402 ms 2680 KB Output is correct
86 Correct 330 ms 2644 KB Output is correct
87 Correct 332 ms 2612 KB Output is correct
88 Correct 347 ms 2520 KB Output is correct
89 Correct 345 ms 2556 KB Output is correct
90 Correct 355 ms 2520 KB Output is correct
91 Correct 324 ms 2524 KB Output is correct
92 Correct 373 ms 2520 KB Output is correct