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Submission #258450

# Submission time Handle Problem Language Result Execution time Memory
258450 2020-08-05T23:45:42 Z c4ts0up Mecho (IOI09_mecho) C++17
21 / 100
 873 ms 35064 KB 
/*
ID: c4ts0up
LANG: C++
TASK: Mecho
*/

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define ff first
#define ss second

const int NMAX = 805;
const int INF = 1e9;

int n, s;
pair <int,int> home, mecho;
char grid[NMAX][NMAX];
int dist[NMAX][NMAX];

// hace el check a una coordenada
bool Check(int row, int col) {
	return (0 <= row && row < n && 0 <= col && col < n);
}

// BFS para encontrar el tiempo requerido para que las abejas lleguen a un lugar
void EncontrarDistancias() {
	queue <pair <int,int> > to;
	set <pair <int,int> > seen;
	
	for (int i=0; i<n; i++) for (int j=0; j<n; j++) {
		if (grid[i][j] == 'H') to.push({i,j}), dist[i][j] = 0;
		else dist[i][j] = INF;
	}

	while (!to.empty()) {
		pair <int,int> curr = to.front();
		to.pop();
		
		// ya lo visitamos
		if (seen.count(curr)) continue;
		
		if (grid[curr.ff][curr.ss] == 'T') {
			seen.insert(curr);
			continue;
		}
		
		// visitamos a todos los vecinos
		if (!seen.count({curr.ff+1, curr.ss}) && Check(curr.ff+1, curr.ss)) to.push({curr.ff+1, curr.ss}), dist[curr.ff+1][curr.ss] = min(dist[curr.ff+1][curr.ss], dist[curr.ff][curr.ss]+1);
		if (!seen.count({curr.ff-1, curr.ss}) && Check(curr.ff-1, curr.ss)) to.push({curr.ff-1, curr.ss}), dist[curr.ff-1][curr.ss] = min(dist[curr.ff-1][curr.ss], dist[curr.ff][curr.ss]+1);
		if (!seen.count({curr.ff, curr.ss+1}) && Check(curr.ff, curr.ss+1)) to.push({curr.ff, curr.ss+1}), dist[curr.ff][curr.ss+1] = min(dist[curr.ff][curr.ss+1], dist[curr.ff][curr.ss]+1);
		if (!seen.count({curr.ff, curr.ss-1}) && Check(curr.ff, curr.ss-1)) to.push({curr.ff, curr.ss-1}), dist[curr.ff][curr.ss-1] = min(dist[curr.ff][curr.ss-1], dist[curr.ff][curr.ss]+1);
		
		seen.insert(curr);
	}
}

bool BFS(int minutos) {
	bool seen[NMAX][NMAX];
	queue <pair <int, pair <int,int> > > to;
	to.push({0, mecho});
	
	for (int i=0; i<=n; i++) for (int j=0; j<=n; j++) seen[i][j] = false;
	
	while (!to.empty()) {
		pair <int, pair <int,int> > curr = to.front();
		to.pop();
		
		int r = curr.ss.ff;
		int c = curr.ss.ss;
		int pasos = curr.ff;
		
		// ya lo visitamos, no tenemos que volver
		if (seen[r][c]) continue;
		
		// no podemos atravesarlo
		if (grid[r][c] == 'T') {
			seen[r][c] = true;
			continue;
		}
		else if (grid[r][c] == 'D') return true;
		
		// ya está infestado de abejas, o sea, bloqueado
		if (minutos + (curr.ff/s) >= dist[r][c]) {
			seen[r][c] = true;
			continue;
		}
		
		// visitamos a todos los vecinos
		
		
		if (!seen[r+1][c] && Check(r+1, c)) to.push({pasos, {r+1,c}});
		if (!seen[r-1][c] && Check(r-1, c)) to.push({pasos, {r-1,c}});
		if (!seen[r][c+1] && Check(r, c+1)) to.push({pasos, {r,c+1}});
		if (!seen[r][c-1] && Check(r, c-1)) to.push({pasos, {r,c-1}});
		
		seen[r][c] = true;
	}
	
	return false;
}


int main() {
	/*//
	freopen("", "r", stdin);
	freopen("", "w", stdout);
	//*/
	
	cin >> n >> s;
	for (int i=0; i<n; i++) {
		string aux;
		cin >> aux;
		for (int j=0; j<n; j++) {
			grid[i][j] = aux[j];
			
			if (grid[i][j] == 'M') mecho = {i,j};
			else if (grid[i][j] == 'D') home = {i,j};
		}
		
		
	}
	
	EncontrarDistancias();
	
	if (!BFS(0)) {
		cout << -1 << endl;
		exit(0);
	}
	
	int lb = 0, ub = 1e6, mid;
	while (lb <= ub) {
		mid = (lb+ub)/2;
		
		if (BFS(mid)) lb = mid+1;
		else ub = mid-1;
	}
	
	//cerr << "lb = " << lb << "; ub = " << ub << "; mid = " << mid << endl;
	cout << ub-1 << endl;
	return 0;
}

Subtask #1
21.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Incorrect 0 ms 384 KB Output isn't correct
3 Correct 1 ms 384 KB Output is correct
4 Incorrect 1 ms 384 KB Output isn't correct
5 Incorrect 1 ms 384 KB Output isn't correct
6 Incorrect 1 ms 384 KB Output isn't correct
7 Incorrect 848 ms 34808 KB Output isn't correct
8 Incorrect 1 ms 384 KB Output isn't correct
9 Incorrect 1 ms 384 KB Output isn't correct
10 Incorrect 1 ms 384 KB Output isn't correct
11 Incorrect 1 ms 384 KB Output isn't correct
12 Incorrect 2 ms 768 KB Output isn't correct
13 Incorrect 2 ms 640 KB Output isn't correct
14 Incorrect 3 ms 768 KB Output isn't correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 512 KB Output is correct
18 Correct 1 ms 512 KB Output is correct
19 Correct 2 ms 512 KB Output is correct
20 Correct 1 ms 512 KB Output is correct
21 Correct 1 ms 640 KB Output is correct
22 Correct 1 ms 640 KB Output is correct
23 Correct 2 ms 640 KB Output is correct
24 Correct 2 ms 640 KB Output is correct
25 Correct 3 ms 768 KB Output is correct
26 Correct 2 ms 768 KB Output is correct
27 Correct 4 ms 896 KB Output is correct
28 Correct 4 ms 824 KB Output is correct
29 Correct 3 ms 896 KB Output is correct
30 Correct 3 ms 896 KB Output is correct
31 Correct 3 ms 896 KB Output is correct
32 Correct 4 ms 896 KB Output is correct
33 Correct 65 ms 7800 KB Output is correct
34 Correct 68 ms 7800 KB Output is correct
35 Incorrect 136 ms 7800 KB Output isn't correct
36 Correct 96 ms 9848 KB Output is correct
37 Correct 98 ms 9848 KB Output is correct
38 Incorrect 182 ms 9848 KB Output isn't correct
39 Correct 102 ms 12152 KB Output is correct
40 Correct 125 ms 12152 KB Output is correct
41 Incorrect 228 ms 12320 KB Output isn't correct
42 Correct 136 ms 14712 KB Output is correct
43 Correct 147 ms 14656 KB Output is correct
44 Incorrect 293 ms 14676 KB Output isn't correct
45 Correct 157 ms 17400 KB Output is correct
46 Correct 178 ms 17400 KB Output is correct
47 Incorrect 358 ms 17400 KB Output isn't correct
48 Correct 198 ms 20472 KB Output is correct
49 Correct 213 ms 20344 KB Output is correct
50 Incorrect 430 ms 20472 KB Output isn't correct
51 Correct 228 ms 23672 KB Output is correct
52 Correct 263 ms 23708 KB Output is correct
53 Incorrect 543 ms 23704 KB Output isn't correct
54 Correct 261 ms 27128 KB Output is correct
55 Correct 292 ms 27256 KB Output is correct
56 Incorrect 617 ms 27256 KB Output isn't correct
57 Correct 315 ms 30840 KB Output is correct
58 Correct 338 ms 30968 KB Output is correct
59 Incorrect 735 ms 30840 KB Output isn't correct
60 Correct 398 ms 34864 KB Output is correct
61 Correct 399 ms 34808 KB Output is correct
62 Incorrect 823 ms 34936 KB Output isn't correct
63 Incorrect 838 ms 34540 KB Output isn't correct
64 Correct 846 ms 34424 KB Output is correct
65 Incorrect 844 ms 34428 KB Output isn't correct
66 Incorrect 836 ms 34424 KB Output isn't correct
67 Incorrect 802 ms 34552 KB Output isn't correct
68 Incorrect 873 ms 34552 KB Output isn't correct
69 Incorrect 807 ms 34552 KB Output isn't correct
70 Incorrect 796 ms 34552 KB Output isn't correct
71 Incorrect 778 ms 34536 KB Output isn't correct
72 Incorrect 727 ms 34552 KB Output isn't correct
73 Incorrect 822 ms 34792 KB Output isn't correct
74 Correct 859 ms 34812 KB Output is correct
75 Incorrect 872 ms 34816 KB Output isn't correct
76 Incorrect 840 ms 34936 KB Output isn't correct
77 Incorrect 854 ms 34772 KB Output isn't correct
78 Incorrect 770 ms 34808 KB Output isn't correct
79 Correct 760 ms 34808 KB Output is correct
80 Incorrect 780 ms 34896 KB Output isn't correct
81 Incorrect 774 ms 34864 KB Output isn't correct
82 Incorrect 740 ms 34808 KB Output isn't correct
83 Incorrect 763 ms 34808 KB Output isn't correct
84 Correct 791 ms 34808 KB Output is correct
85 Incorrect 780 ms 34808 KB Output isn't correct
86 Incorrect 795 ms 34940 KB Output isn't correct
87 Incorrect 796 ms 35064 KB Output isn't correct
88 Incorrect 802 ms 34808 KB Output isn't correct
89 Correct 805 ms 34808 KB Output is correct
90 Incorrect 816 ms 34808 KB Output isn't correct
91 Incorrect 848 ms 34768 KB Output isn't correct
92 Incorrect 805 ms 35000 KB Output isn't correct