oj.uz

답안 #621482

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
621482 2022-08-03T21:08:08 Z abcisosm5 Mecho (IOI09_mecho) C++17
100 / 100
 314 ms 2752 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<pair<pi,int>> (&b), char (&v)[MN][MN], int t){
	if(b.empty()) return; 
	int start = b.front().s;
	for(int i = 0; i < t; i++){
		while(!b.empty() && b.front().s <= start + i){
			pair<pi, int> x = b.front(); b.pop();
			pi p = x.f; int index = x.s;
			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' || grid[nx][ny] == 'M')){
					v[nx][ny] = 'B';
					b.push({{nx, ny}, index+1});
				}
			}
		}
	}
}

bool movemecho(queue<pair<pi, int>> (&m), char (&v)[MN][MN]){
	if(m.empty()) return false; 
	int start = m.front().s;
	for(int i = 0; i < S; i++){
		while(!m.empty() && m.front().s <= start + i){
			pair<pi, int> x = m.front(); m.pop();
			pi p = x.f; int index = x.s;
			if(v[p.f][p.s] == 'B') continue; //invalidate positions that are now occupied by bees
			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'){
					v[nx][ny] = 'M';
					if(grid[nx][ny] == 'D') return true;
					m.push({{nx, ny}, index+1});
				}
			}
		}
	}
	return false;
}

bool works(int t){ //O(N^2)
	char visited[MN][MN] = {{}};
	queue<pair<pi, int>> mecho; mecho.push({M,0}); visited[M.f][M.s] = 'M';
	queue<pair<pi, int>> bees;
	for(pi p : hives){
		bees.push({p,0});
		visited[p.first][p.second] = 'B'; 
	}
	movebees(bees, visited, t);
	
	for(int i = 0; i < N*N; 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; //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;
}

Subtask #1
100.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 836 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 852 KB Output is correct
4 Correct 1 ms 852 KB Output is correct
5 Correct 1 ms 852 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 259 ms 2344 KB Output is correct
8 Correct 1 ms 852 KB Output is correct
9 Correct 1 ms 840 KB Output is correct
10 Correct 1 ms 852 KB Output is correct
11 Correct 1 ms 852 KB Output is correct
12 Correct 3 ms 980 KB Output is correct
13 Correct 2 ms 980 KB Output is correct
14 Correct 3 ms 972 KB Output is correct
15 Correct 1 ms 852 KB Output is correct
16 Correct 1 ms 936 KB Output is correct
17 Correct 1 ms 852 KB Output is correct
18 Correct 1 ms 852 KB Output is correct
19 Correct 1 ms 968 KB Output is correct
20 Correct 1 ms 968 KB Output is correct
21 Correct 1 ms 968 KB Output is correct
22 Correct 1 ms 980 KB Output is correct
23 Correct 1 ms 980 KB Output is correct
24 Correct 1 ms 980 KB Output is correct
25 Correct 2 ms 964 KB Output is correct
26 Correct 2 ms 980 KB Output is correct
27 Correct 2 ms 976 KB Output is correct
28 Correct 2 ms 980 KB Output is correct
29 Correct 2 ms 980 KB Output is correct
30 Correct 2 ms 980 KB Output is correct
31 Correct 2 ms 972 KB Output is correct
32 Correct 2 ms 980 KB Output is correct
33 Correct 23 ms 1236 KB Output is correct
34 Correct 21 ms 1236 KB Output is correct
35 Correct 33 ms 1328 KB Output is correct
36 Correct 32 ms 1364 KB Output is correct
37 Correct 31 ms 1364 KB Output is correct
38 Correct 39 ms 1408 KB Output is correct
39 Correct 39 ms 1492 KB Output is correct
40 Correct 37 ms 1488 KB Output is correct
41 Correct 54 ms 1492 KB Output is correct
42 Correct 53 ms 1476 KB Output is correct
43 Correct 44 ms 1568 KB Output is correct
44 Correct 65 ms 1492 KB Output is correct
45 Correct 72 ms 1772 KB Output is correct
46 Correct 54 ms 1660 KB Output is correct
47 Correct 77 ms 1620 KB Output is correct
48 Correct 69 ms 1876 KB Output is correct
49 Correct 65 ms 1868 KB Output is correct
50 Correct 95 ms 1760 KB Output is correct
51 Correct 108 ms 1852 KB Output is correct
52 Correct 81 ms 1876 KB Output is correct
53 Correct 115 ms 1872 KB Output is correct
54 Correct 98 ms 1876 KB Output is correct
55 Correct 125 ms 1964 KB Output is correct
56 Correct 139 ms 1876 KB Output is correct
57 Correct 112 ms 2072 KB Output is correct
58 Correct 103 ms 2004 KB Output is correct
59 Correct 166 ms 2088 KB Output is correct
60 Correct 134 ms 2172 KB Output is correct
61 Correct 117 ms 2176 KB Output is correct
62 Correct 176 ms 2212 KB Output is correct
63 Correct 264 ms 2196 KB Output is correct
64 Correct 283 ms 2192 KB Output is correct
65 Correct 268 ms 2196 KB Output is correct
66 Correct 285 ms 2240 KB Output is correct
67 Correct 266 ms 2188 KB Output is correct
68 Correct 290 ms 2252 KB Output is correct
69 Correct 238 ms 2232 KB Output is correct
70 Correct 248 ms 2232 KB Output is correct
71 Correct 303 ms 2252 KB Output is correct
72 Correct 299 ms 2352 KB Output is correct
73 Correct 226 ms 2596 KB Output is correct
74 Correct 286 ms 2752 KB Output is correct
75 Correct 284 ms 2644 KB Output is correct
76 Correct 281 ms 2656 KB Output is correct
77 Correct 292 ms 2632 KB Output is correct
78 Correct 290 ms 2568 KB Output is correct
79 Correct 273 ms 2700 KB Output is correct
80 Correct 314 ms 2560 KB Output is correct
81 Correct 291 ms 2548 KB Output is correct
82 Correct 290 ms 2576 KB Output is correct
83 Correct 297 ms 2516 KB Output is correct
84 Correct 304 ms 2508 KB Output is correct
85 Correct 291 ms 2516 KB Output is correct
86 Correct 297 ms 2580 KB Output is correct
87 Correct 287 ms 2516 KB Output is correct
88 Correct 277 ms 2428 KB Output is correct
89 Correct 266 ms 2432 KB Output is correct
90 Correct 275 ms 2340 KB Output is correct
91 Correct 269 ms 2336 KB Output is correct
92 Correct 306 ms 2436 KB Output is correct