Submission #763902

# Submission time Handle Problem Language Result Execution time Memory
763902 2023-06-23T02:54:32 Z hanlulu Mecho (IOI09_mecho) C++14
38 / 100
184 ms 6556 KB
//https://cses.fi/problemset/task/1707
#include <bits/stdc++.h>
using namespace std; 
/*
有点像793的题目,两次最短。Bee走出到每一个位置的最短,
然后二分答案,然后Mecho走最短的时侯每一个相邻是否可以走需要计算是否Bee先到。
如何处理一分钟走s步这里?dis记录当前的步数,每次走到相邻+1,但是时间可以用dis/s得到。
注意:一个位置如果bee先到,比如2s到,m 3s到,那么m就不能走,如果相等可以走,因为每一次都是m先走。
但是,终点要特殊处理。 
*/
int n,s;
char a[801][801];
int rdir[4] = {0,0,1,-1};
int cdir[4] = {1,-1,0,0};
vector<vector<int>> beetime(801,vector<int>(801,1e9));

int sx,sy,ex,ey;//起点和终点 

bool isok(int eat)//eat is how many time he stay at start point. 
{
	vector<vector<int>> mstep(801,vector<int>(801,1e9));
	//cout << eat << endl;
	queue<pair<int,int>> myq;
	mstep[sx][sy] = 0;
	myq.push({sx,sy}); 
	while (!myq.empty()) {
		int x = myq.front().first;
		int y = myq.front().second;
		myq.pop();
		for (int i = 0; i < 4; i++)
		{
			int newx = x + rdir[i];
			int newy = y + cdir[i];
			if (a[newx][newy] == 'D') return true;//终点不需要判断了。因为bee到不了。 
			if (newx <0 || newx == n || newy < 0 || newy == n) continue;
			if (a[newx][newy] == 'T' || a[newx][newy] == 'H') continue;
			if (mstep[newx][newy] <= mstep[x][y] + 1) continue;
			if (beetime[newx][newy] < ceil(1.0*(mstep[x][y]+1) /s) + eat) continue; 
			//cout << newx << " " << newy << " " << (mstep[x][y]+1) /s + eat << endl;
			mstep[newx][newy] = mstep[x][y] + 1;
			
			myq.push({newx,newy});
		}		
	}
	//cout <<  mstep[2][2]  << endl;
	return mstep[ex][ey] != 1e9;
}
int main()
{
  	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	//freopen("nocross.in","r",stdin);
	//freopen("nocross.out","w",stdout);
 	cin >> n >> s;
	
	queue<pair<int,int>> myq;
 	for (int i = 0; i < n; i++) 
 	for (int j = 0; j < n; j++) 
 	{
 		cin >> a[i][j];
 		if (a[i][j] == 'M') sx = i, sy = j;
 		if (a[i][j] == 'D') ex = i, ey = j;
 		if (a[i][j] == 'H') {
 			beetime[i][j] = 0;
 			myq.push({i,j});
		};
	}	

  	//find beetime
	while (!myq.empty()) {
		int x = myq.front().first;
		int y = myq.front().second;
		myq.pop();
		for (int i = 0; i < 4; i++)
		{
			int newx = x + rdir[i];
			int newy = y + cdir[i];
			if (newx <0 || newx == n || newy < 0 || newy == n) continue;
			if (a[newx][newy] == 'T' ||  a[newx][newy] == 'H') continue;
			if (beetime[newx][newy] <= beetime[x][y] + 1) continue;
			
			beetime[newx][newy] = beetime[x][y] + 1;
			
			if (a[newx][newy] != 'D' )//can not go throuh home, but need know the time bee arrive
 				myq.push({newx,newy});
		}
	}
	  //	cout << beetime[2][2]<< endl;
  	//bin the answer
  	int ans = -1;
  	int l = 0, r =  n*n, mid;
  	while (l <= r) {
  		mid = (l+r)/2;
  		//cout << "mid " << mid <<  endl;
		if (isok(mid)) {
			ans = mid;
			l = mid + 1;
		}	
		else r = mid - 1;
	}
	cout << ans << '\n'; 
	return 0;
}
# Verdict Execution time Memory Grader output
1 Incorrect 4 ms 5392 KB Output isn't correct
2 Incorrect 4 ms 5388 KB Output isn't correct
3 Incorrect 5 ms 5412 KB Output isn't correct
4 Incorrect 5 ms 5412 KB Output isn't correct
5 Correct 5 ms 5432 KB Output is correct
6 Correct 6 ms 5420 KB Output is correct
7 Correct 120 ms 6100 KB Output is correct
8 Incorrect 8 ms 5420 KB Output isn't correct
9 Correct 7 ms 5452 KB Output is correct
10 Correct 7 ms 5420 KB Output is correct
11 Correct 6 ms 5432 KB Output is correct
12 Incorrect 9 ms 5472 KB Output isn't correct
13 Incorrect 9 ms 5452 KB Output isn't correct
14 Correct 8 ms 5476 KB Output is correct
15 Incorrect 8 ms 5448 KB Output isn't correct
16 Correct 7 ms 5444 KB Output is correct
17 Incorrect 7 ms 5452 KB Output isn't correct
18 Correct 8 ms 5452 KB Output is correct
19 Incorrect 8 ms 5452 KB Output isn't correct
20 Correct 8 ms 5440 KB Output is correct
21 Incorrect 9 ms 5512 KB Output isn't correct
22 Correct 8 ms 5472 KB Output is correct
23 Incorrect 8 ms 5472 KB Output isn't correct
24 Correct 9 ms 5472 KB Output is correct
25 Incorrect 9 ms 5484 KB Output isn't correct
26 Correct 9 ms 5472 KB Output is correct
27 Incorrect 9 ms 5492 KB Output isn't correct
28 Correct 10 ms 5488 KB Output is correct
29 Incorrect 10 ms 5552 KB Output isn't correct
30 Correct 10 ms 5480 KB Output is correct
31 Incorrect 9 ms 5492 KB Output isn't correct
32 Correct 10 ms 5528 KB Output is correct
33 Incorrect 13 ms 5740 KB Output isn't correct
34 Correct 14 ms 5740 KB Output is correct
35 Correct 35 ms 5724 KB Output is correct
36 Incorrect 15 ms 5776 KB Output isn't correct
37 Correct 16 ms 5772 KB Output is correct
38 Correct 42 ms 5772 KB Output is correct
39 Incorrect 17 ms 5808 KB Output isn't correct
40 Correct 16 ms 5816 KB Output is correct
41 Correct 53 ms 5788 KB Output is correct
42 Incorrect 17 ms 5856 KB Output isn't correct
43 Correct 17 ms 5848 KB Output is correct
44 Correct 77 ms 5840 KB Output is correct
45 Incorrect 18 ms 5908 KB Output isn't correct
46 Correct 18 ms 5888 KB Output is correct
47 Correct 73 ms 5888 KB Output is correct
48 Incorrect 20 ms 5948 KB Output isn't correct
49 Correct 20 ms 5948 KB Output is correct
50 Correct 85 ms 5916 KB Output is correct
51 Incorrect 27 ms 5948 KB Output isn't correct
52 Correct 27 ms 5960 KB Output is correct
53 Correct 100 ms 5968 KB Output is correct
54 Incorrect 21 ms 6016 KB Output isn't correct
55 Correct 22 ms 6020 KB Output is correct
56 Correct 134 ms 6012 KB Output is correct
57 Incorrect 23 ms 6052 KB Output isn't correct
58 Correct 23 ms 6060 KB Output is correct
59 Correct 141 ms 6032 KB Output is correct
60 Incorrect 25 ms 6096 KB Output isn't correct
61 Correct 28 ms 6080 KB Output is correct
62 Correct 150 ms 6060 KB Output is correct
63 Correct 110 ms 6056 KB Output is correct
64 Correct 184 ms 6052 KB Output is correct
65 Correct 138 ms 6056 KB Output is correct
66 Incorrect 124 ms 6076 KB Output isn't correct
67 Correct 112 ms 6024 KB Output is correct
68 Correct 52 ms 6096 KB Output is correct
69 Correct 62 ms 6148 KB Output is correct
70 Correct 43 ms 6076 KB Output is correct
71 Correct 46 ms 6092 KB Output is correct
72 Incorrect 35 ms 6168 KB Output isn't correct
73 Incorrect 49 ms 6112 KB Output isn't correct
74 Correct 73 ms 6084 KB Output is correct
75 Correct 88 ms 6044 KB Output is correct
76 Correct 87 ms 6084 KB Output is correct
77 Correct 79 ms 6116 KB Output is correct
78 Correct 115 ms 6068 KB Output is correct
79 Correct 59 ms 6084 KB Output is correct
80 Correct 75 ms 6104 KB Output is correct
81 Correct 82 ms 6080 KB Output is correct
82 Correct 79 ms 6556 KB Output is correct
83 Correct 96 ms 6136 KB Output is correct
84 Correct 90 ms 6072 KB Output is correct
85 Correct 94 ms 6096 KB Output is correct
86 Correct 92 ms 6084 KB Output is correct
87 Correct 96 ms 6064 KB Output is correct
88 Correct 97 ms 6076 KB Output is correct
89 Correct 102 ms 6144 KB Output is correct
90 Correct 102 ms 6088 KB Output is correct
91 Correct 115 ms 6092 KB Output is correct
92 Correct 120 ms 6172 KB Output is correct