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Submission #103686

# Submission time Handle Problem Language Result Execution time Memory
103686 2019-04-02T04:25:33 Z tugushka Mecho (IOI09_mecho) C++14
46 / 100
 551 ms 66560 KB 
#include<bits/stdc++.h>
#define mp make_pair
#define pb push_back
using namespace std;

using pii = pair < short, short >;
const int N = 805;
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1};

char a[N][N];
pii mecho, home;
int n, s, hive[N][N];
bool used[N][N];

void hive_bfs(){
	memset( hive, 11, sizeof(hive) );
	queue < pii > q;
	for(int i = 0 ; i < n ; i++) for(int j = 0 ; j < n ; j++){
		if( a[i][j] == 'H' ){
			q.push( mp( i, j ) );
			hive[i][j] = 0;
		}
	}

	int dis = 0;
	while( !q.empty() ){
		dis += s;
		int sz = q.size();
		while( sz-- ){
			short int x, y;
			tie(x, y) = q.front();
			q.pop();
			for(int i = 0 ; i < 4 ; i++){
				short int tx = x+dx[i], ty = y+dy[i];
				if( tx < 0 || ty < 0 || tx >= n || ty >= n ) continue;
				if( a[tx][ty] == 'G' && hive[tx][ty] > 2e6 ){
					hive[tx][ty] = dis;
					q.push( mp( tx, ty ) );
				}
			}
		}
	}

	/*
	for(int i = 0 ; i < n ; i++){
		for(int j = 0 ; j < n ; j++){
			if( hive[i][j] > 2e6 ) printf("@@ ");
			else printf("%2d ", hive[i][j]);
		}
		printf("\n");
	}
	*/
}

bool mecho_bfs(int start_time){
	memset( used, 0, sizeof(used) );

	if( start_time > hive[home.first][home.second] ){
		return false;
	}

	queue < pii > q;
	q.push( mecho );

	int dis = start_time;
	while( !q.empty() ){
		dis++;
		// cout << "dis " << dis << " : ";

		int sz = q.size();
		while( sz-- ){
			short int x, y;
			tie(x, y) = q.front();
			q.pop();
			for(int i = 0 ; i < 4 ; i++){
				short int tx = x+dx[i], ty = y+dy[i];
				if( tx < 0 || ty < 0 || tx >= n || ty >= n ) continue;
				if( !used[tx][ty] && a[tx][ty] == 'G' && hive[tx][ty] > dis ){
					used[tx][ty] = 1;
					if( used[ home.first ][ home.second ] ){
						return true;
					}
					// cout << "( " << tx << ',' << ty << " ), ";
					q.push( mp( tx, ty ) );
				}
			}
		}
		// cout << endl;
	}

	return used[ home.first ][ home.second ];
}

int main(){
	scanf("%d %d", &n, &s);
	for(int i = 0 ; i < n ; i++){
		scanf("%s", a[i]);
	}
	
	for(int i = 0 ; i < n ; i++) for(int j = 0 ; j < n ; j++){
		if( a[i][j] == 'D' ){
			home = mp( i, j );
			a[i][j] = 'G';
		}
		if( a[i][j] == 'M' ){
			mecho = mp( i, j );
		}
	}
	hive_bfs();

	if( !mecho_bfs( 0 ) ){
		printf("-1\n");
		return 0;
	}

	int l = 0, r = n*n, res;
	while( l <= r ){
		int mid = (l+r)/2;

		if( mecho_bfs( s*(mid) ) ){
			res = mid;
			l = mid+1;
		} else {
			r = mid-1;
		}
	}

	/*
	int res = 0;
	while( mecho_bfs( s*(res+1) ) ) res++;
	*/
	cout << res << endl;
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:95:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &s);
  ~~~~~^~~~~~~~~~~~~~~~~
mecho.cpp:97:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s", a[i]);
   ~~~~~^~~~~~~~~~~~
mecho.cpp:132:10: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout << res << endl;
          ^~~

Subtask #1
46.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3456 KB Output is correct
2 Incorrect 5 ms 3456 KB Output isn't correct
3 Correct 6 ms 3456 KB Output is correct
4 Incorrect 6 ms 3456 KB Output isn't correct
5 Correct 5 ms 3456 KB Output is correct
6 Incorrect 6 ms 3456 KB Output isn't correct
7 Incorrect 76 ms 4096 KB Output isn't correct
8 Correct 6 ms 3456 KB Output is correct
9 Correct 5 ms 3456 KB Output is correct
10 Correct 5 ms 3456 KB Output is correct
11 Correct 5 ms 3456 KB Output is correct
12 Incorrect 5 ms 3584 KB Output isn't correct
13 Incorrect 6 ms 3584 KB Output isn't correct
14 Correct 5 ms 3584 KB Output is correct
15 Correct 5 ms 3456 KB Output is correct
16 Correct 5 ms 3584 KB Output is correct
17 Correct 6 ms 3584 KB Output is correct
18 Correct 5 ms 3456 KB Output is correct
19 Correct 6 ms 3584 KB Output is correct
20 Correct 5 ms 3456 KB Output is correct
21 Correct 5 ms 3456 KB Output is correct
22 Correct 5 ms 3584 KB Output is correct
23 Correct 5 ms 3456 KB Output is correct
24 Correct 6 ms 3584 KB Output is correct
25 Correct 5 ms 3584 KB Output is correct
26 Correct 5 ms 3584 KB Output is correct
27 Correct 6 ms 3556 KB Output is correct
28 Correct 5 ms 3584 KB Output is correct
29 Correct 6 ms 3584 KB Output is correct
30 Correct 6 ms 3584 KB Output is correct
31 Correct 5 ms 3584 KB Output is correct
32 Correct 6 ms 3584 KB Output is correct
33 Correct 9 ms 3712 KB Output is correct
34 Runtime error 505 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
35 Correct 18 ms 3840 KB Output is correct
36 Correct 8 ms 3840 KB Output is correct
37 Runtime error 499 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
38 Correct 21 ms 3840 KB Output is correct
39 Correct 11 ms 3840 KB Output is correct
40 Runtime error 490 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
41 Correct 22 ms 3812 KB Output is correct
42 Correct 9 ms 3968 KB Output is correct
43 Runtime error 519 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
44 Correct 34 ms 3968 KB Output is correct
45 Correct 12 ms 3968 KB Output is correct
46 Runtime error 551 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
47 Correct 38 ms 3968 KB Output is correct
48 Correct 14 ms 3968 KB Output is correct
49 Runtime error 468 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
50 Correct 51 ms 4088 KB Output is correct
51 Correct 14 ms 3968 KB Output is correct
52 Runtime error 493 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
53 Correct 54 ms 3964 KB Output is correct
54 Correct 16 ms 3968 KB Output is correct
55 Runtime error 453 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
56 Correct 68 ms 4096 KB Output is correct
57 Correct 14 ms 4096 KB Output is correct
58 Runtime error 473 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
59 Correct 75 ms 4216 KB Output is correct
60 Correct 18 ms 4096 KB Output is correct
61 Runtime error 477 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
62 Correct 85 ms 4088 KB Output is correct
63 Correct 150 ms 4096 KB Output is correct
64 Runtime error 439 ms 66560 KB Execution killed with signal 9 (could be triggered by violating memory limits)
65 Correct 171 ms 4216 KB Output is correct
66 Correct 166 ms 4060 KB Output is correct
67 Correct 34 ms 4096 KB Output is correct
68 Correct 53 ms 4096 KB Output is correct
69 Correct 61 ms 4088 KB Output is correct
70 Correct 39 ms 4096 KB Output is correct
71 Correct 47 ms 4088 KB Output is correct
72 Incorrect 37 ms 4088 KB Output isn't correct
73 Incorrect 95 ms 4204 KB Output isn't correct
74 Correct 72 ms 4324 KB Output is correct
75 Correct 78 ms 4204 KB Output is correct
76 Correct 67 ms 4212 KB Output is correct
77 Correct 62 ms 4212 KB Output is correct
78 Correct 31 ms 4344 KB Output is correct
79 Correct 63 ms 4316 KB Output is correct
80 Correct 67 ms 4216 KB Output is correct
81 Correct 76 ms 4216 KB Output is correct
82 Correct 64 ms 4224 KB Output is correct
83 Correct 72 ms 4304 KB Output is correct
84 Correct 76 ms 4316 KB Output is correct
85 Correct 87 ms 4224 KB Output is correct
86 Correct 82 ms 4300 KB Output is correct
87 Correct 88 ms 4224 KB Output is correct
88 Correct 78 ms 4224 KB Output is correct
89 Correct 70 ms 4176 KB Output is correct
90 Correct 91 ms 4216 KB Output is correct
91 Correct 97 ms 4344 KB Output is correct
92 Correct 99 ms 4216 KB Output is correct