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답안 #763904

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
763904 2023-06-23T02:59:56 Z hanlulu Mecho (IOI09_mecho) C++14
84 / 100
 173 ms 6184 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; 
			if (beetime[newx][newy] <= (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 false;
}
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;
}

Subtask #1
84.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 5460 KB Output is correct
2 Correct 5 ms 5412 KB Output is correct
3 Correct 5 ms 5392 KB Output is correct
4 Correct 5 ms 5404 KB Output is correct
5 Correct 6 ms 5432 KB Output is correct
6 Correct 6 ms 5432 KB Output is correct
7 Correct 89 ms 6064 KB Output is correct
8 Correct 7 ms 5432 KB Output is correct
9 Correct 7 ms 5440 KB Output is correct
10 Correct 7 ms 5432 KB Output is correct
11 Correct 7 ms 5432 KB Output is correct
12 Incorrect 9 ms 5492 KB Output isn't correct
13 Incorrect 9 ms 5600 KB Output isn't correct
14 Correct 10 ms 5472 KB Output is correct
15 Correct 7 ms 5432 KB Output is correct
16 Correct 6 ms 5432 KB Output is correct
17 Correct 8 ms 5452 KB Output is correct
18 Correct 8 ms 5452 KB Output is correct
19 Correct 8 ms 5452 KB Output is correct
20 Correct 8 ms 5496 KB Output is correct
21 Correct 8 ms 5512 KB Output is correct
22 Correct 10 ms 5472 KB Output is correct
23 Correct 9 ms 5472 KB Output is correct
24 Correct 9 ms 5472 KB Output is correct
25 Correct 9 ms 5480 KB Output is correct
26 Correct 10 ms 5472 KB Output is correct
27 Correct 9 ms 5552 KB Output is correct
28 Correct 10 ms 5492 KB Output is correct
29 Correct 9 ms 5552 KB Output is correct
30 Correct 10 ms 5500 KB Output is correct
31 Correct 9 ms 5492 KB Output is correct
32 Correct 10 ms 5492 KB Output is correct
33 Correct 14 ms 5740 KB Output is correct
34 Correct 14 ms 5744 KB Output is correct
35 Correct 29 ms 5724 KB Output is correct
36 Correct 15 ms 5764 KB Output is correct
37 Correct 16 ms 5772 KB Output is correct
38 Correct 35 ms 5732 KB Output is correct
39 Correct 15 ms 5808 KB Output is correct
40 Correct 18 ms 5808 KB Output is correct
41 Correct 46 ms 5808 KB Output is correct
42 Correct 17 ms 5848 KB Output is correct
43 Correct 17 ms 5844 KB Output is correct
44 Correct 51 ms 5836 KB Output is correct
45 Correct 19 ms 5888 KB Output is correct
46 Correct 18 ms 5928 KB Output is correct
47 Correct 56 ms 5892 KB Output is correct
48 Correct 19 ms 6012 KB Output is correct
49 Correct 20 ms 5944 KB Output is correct
50 Correct 66 ms 5916 KB Output is correct
51 Correct 21 ms 5964 KB Output is correct
52 Correct 21 ms 5980 KB Output is correct
53 Correct 78 ms 5952 KB Output is correct
54 Correct 28 ms 6000 KB Output is correct
55 Correct 22 ms 6004 KB Output is correct
56 Correct 90 ms 5988 KB Output is correct
57 Correct 28 ms 6136 KB Output is correct
58 Correct 23 ms 6048 KB Output is correct
59 Correct 102 ms 6024 KB Output is correct
60 Correct 24 ms 6096 KB Output is correct
61 Correct 24 ms 6096 KB Output is correct
62 Correct 137 ms 6088 KB Output is correct
63 Correct 98 ms 6056 KB Output is correct
64 Correct 173 ms 6168 KB Output is correct
65 Correct 128 ms 6048 KB Output is correct
66 Correct 111 ms 6052 KB Output is correct
67 Correct 115 ms 6060 KB Output is correct
68 Correct 51 ms 6080 KB Output is correct
69 Correct 52 ms 6084 KB Output is correct
70 Correct 39 ms 6096 KB Output is correct
71 Correct 45 ms 6072 KB Output is correct
72 Incorrect 37 ms 6096 KB Output isn't correct
73 Incorrect 45 ms 6120 KB Output isn't correct
74 Correct 59 ms 6092 KB Output is correct
75 Correct 77 ms 6068 KB Output is correct
76 Correct 85 ms 6076 KB Output is correct
77 Correct 68 ms 6060 KB Output is correct
78 Correct 76 ms 6092 KB Output is correct
79 Correct 54 ms 6092 KB Output is correct
80 Correct 62 ms 6096 KB Output is correct
81 Correct 68 ms 6084 KB Output is correct
82 Correct 62 ms 6100 KB Output is correct
83 Correct 79 ms 6096 KB Output is correct
84 Correct 71 ms 6104 KB Output is correct
85 Correct 78 ms 6080 KB Output is correct
86 Correct 75 ms 6084 KB Output is correct
87 Correct 77 ms 6096 KB Output is correct
88 Correct 94 ms 6184 KB Output is correct
89 Correct 81 ms 6076 KB Output is correct
90 Correct 93 ms 6112 KB Output is correct
91 Correct 83 ms 6080 KB Output is correct
92 Correct 96 ms 6068 KB Output is correct