Submission #948111

# Submission time Handle Problem Language Result Execution time Memory
948111 2024-03-17T15:21:44 Z packmani Mecho (IOI09_mecho) C++14
84 / 100
161 ms 7504 KB
#include<bits/stdc++.h>
using namespace std;
#define int long long int
int n,speed;
char inp[805][805];
int board[805][805];
bool visited[805][805];
queue<pair<int,int>> q;
pair<int,int> s,e;
int cr,cc,er,ec;
int dr[]={0,-1,0,1};
int dc[]={1,0,-1,0};
int maxTime=0;
int l,m,r;
int layer,tillNext,inNext;
bool bfs(int start)
{
	queue<pair<int,int>> tempq;
	memset(visited,0,sizeof(visited));
	int time=start;
	tempq.push({s.first,s.second});
	tillNext=1;
	inNext=0;
	layer=0;
	while(!tempq.empty())
	{
		cr = tempq.front().first;
		cc = tempq.front().second;
		tempq.pop();
		if(board[cr][cc]>time or inp[cr][cc]=='M')//bees have not reached this spot yet
		{
			//cout << time;
			for(int i=0;i<4;i++)
			{
				er = cr + dr[i];
				ec = cc + dc[i];
				if(er<0 or ec<0 or er>=n or ec>=n) continue;
				if(inp[er][ec]=='D') return 1;
				if(visited[er][ec]) continue;
				if(board[er][ec]==-1) continue;
				if(board[er][ec]<=time) continue;
				tempq.push({er,ec});
				visited[er][ec]=1;
				inNext++;
			}
		}
		tillNext--;
		if(tillNext==0)
		{
			tillNext = inNext;
			inNext = 0;
			layer++;
			if(layer%speed==0) time++;
		}
	}
	return 0;
}
int32_t main()
{
	cin.tie(0); ios_base::sync_with_stdio(false);
	cin >> n >> speed;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			cin >> inp[i][j];
			if(inp[i][j]=='T') board[i][j]=-1; //no one can traverse
			if(inp[i][j]=='H') 
			{
				board[i][j]=0; //not walkable since the 0th sec
				q.push({i,j});
			}
			if(inp[i][j]=='M') s={i,j};
			if(inp[i][j]=='D') e={i,j};
			if(inp[i][j]=='G') board[i][j] = 1000000;
		}
	}
	//bees
	while(!q.empty())
	{
		cr = q.front().first;
		cc = q.front().second;
		q.pop();
		for(int i=0;i<4;i++)
		{
			er = cr + dr[i];
			ec = cc + dc[i];
			if(er<0 or ec<0 or er>=n or ec>=n) continue;
			if(board[er][ec]==-1 or board[er][ec]=='D' or board[er][ec]=='M') continue;
			if(board[er][ec]<=board[cr][cc]+1) continue;
			board[er][ec]=board[cr][cc]+1;
			q.push({er,ec});
			maxTime=max(maxTime,board[er][ec]);
		}
	}
	l=0;
	r=n*n;
	m = l + (r-l)/2;
	int best=-1;
	while(l<=r)
	{
		//cout << l << ' ' << r << ' ' << m << '\n';
		if(bfs(m)==1) l=m+1;
		else r=m-1;
		m = l + (r+0.5-l)/2;
	}
	if(m==0 and bfs(0)==0) cout << -1;
	else cout << m;
}

Compilation message

mecho.cpp: In function 'int32_t main()':
mecho.cpp:99:6: warning: unused variable 'best' [-Wunused-variable]
   99 |  int best=-1;
      |      ^~~~
# 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 4696 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4700 KB Output is correct
7 Correct 60 ms 7004 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 4700 KB Output is correct
11 Correct 1 ms 4524 KB Output is correct
12 Incorrect 1 ms 4700 KB Output isn't correct
13 Incorrect 1 ms 4700 KB Output isn't correct
14 Correct 1 ms 4700 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 4696 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 4700 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 4700 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 4700 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 3 ms 6744 KB Output is correct
34 Correct 3 ms 6744 KB Output is correct
35 Correct 17 ms 7004 KB Output is correct
36 Correct 4 ms 6748 KB Output is correct
37 Correct 4 ms 6748 KB Output is correct
38 Correct 19 ms 6748 KB Output is correct
39 Correct 5 ms 6748 KB Output is correct
40 Correct 5 ms 6748 KB Output is correct
41 Correct 24 ms 6608 KB Output is correct
42 Correct 6 ms 6744 KB Output is correct
43 Correct 6 ms 6748 KB Output is correct
44 Correct 32 ms 6788 KB Output is correct
45 Correct 7 ms 6616 KB Output is correct
46 Correct 7 ms 6748 KB Output is correct
47 Correct 33 ms 6812 KB Output is correct
48 Correct 8 ms 6748 KB Output is correct
49 Correct 8 ms 6744 KB Output is correct
50 Correct 42 ms 6748 KB Output is correct
51 Correct 9 ms 6744 KB Output is correct
52 Correct 9 ms 6748 KB Output is correct
53 Correct 56 ms 6788 KB Output is correct
54 Correct 10 ms 6748 KB Output is correct
55 Correct 10 ms 6744 KB Output is correct
56 Correct 59 ms 6748 KB Output is correct
57 Correct 11 ms 6748 KB Output is correct
58 Correct 13 ms 6932 KB Output is correct
59 Correct 68 ms 6748 KB Output is correct
60 Correct 12 ms 6744 KB Output is correct
61 Correct 12 ms 6748 KB Output is correct
62 Correct 77 ms 6620 KB Output is correct
63 Correct 97 ms 6788 KB Output is correct
64 Correct 161 ms 6788 KB Output is correct
65 Correct 125 ms 6780 KB Output is correct
66 Correct 98 ms 6736 KB Output is correct
67 Correct 100 ms 6748 KB Output is correct
68 Correct 45 ms 6840 KB Output is correct
69 Correct 40 ms 6676 KB Output is correct
70 Correct 32 ms 6748 KB Output is correct
71 Correct 36 ms 6748 KB Output is correct
72 Incorrect 31 ms 6672 KB Output isn't correct
73 Incorrect 50 ms 7256 KB Output isn't correct
74 Correct 40 ms 7224 KB Output is correct
75 Correct 53 ms 7340 KB Output is correct
76 Correct 45 ms 7248 KB Output is correct
77 Correct 45 ms 7332 KB Output is correct
78 Correct 56 ms 7132 KB Output is correct
79 Correct 34 ms 7260 KB Output is correct
80 Correct 45 ms 7256 KB Output is correct
81 Correct 49 ms 7504 KB Output is correct
82 Correct 43 ms 7260 KB Output is correct
83 Correct 59 ms 7000 KB Output is correct
84 Correct 48 ms 7004 KB Output is correct
85 Correct 53 ms 7200 KB Output is correct
86 Correct 63 ms 7200 KB Output is correct
87 Correct 62 ms 7252 KB Output is correct
88 Correct 58 ms 7256 KB Output is correct
89 Correct 55 ms 7000 KB Output is correct
90 Correct 57 ms 7000 KB Output is correct
91 Correct 58 ms 7004 KB Output is correct
92 Correct 58 ms 6992 KB Output is correct