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답안 #763906

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
763906 2023-06-23T03:01:03 Z hanlulu Mecho (IOI09_mecho) C++14
84 / 100
 169 ms 6192 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。 能到达终点的周围四个点就可以到达。 
*/
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' ||  a[newx][newy] == 'D') continue;
			if (beetime[newx][newy] <= beetime[x][y] + 1) continue;
			
			beetime[newx][newy] = beetime[x][y] + 1;			
			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 4 ms 5392 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 5392 KB Output is correct
5 Correct 5 ms 5388 KB Output is correct
6 Correct 6 ms 5432 KB Output is correct
7 Correct 88 ms 6064 KB Output is correct
8 Correct 6 ms 5432 KB Output is correct
9 Correct 7 ms 5432 KB Output is correct
10 Correct 6 ms 5432 KB Output is correct
11 Correct 8 ms 5448 KB Output is correct
12 Incorrect 9 ms 5464 KB Output isn't correct
13 Incorrect 8 ms 5472 KB Output isn't correct
14 Correct 9 ms 5476 KB Output is correct
15 Correct 7 ms 5432 KB Output is correct
16 Correct 7 ms 5432 KB Output is correct
17 Correct 7 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 7 ms 5452 KB Output is correct
21 Correct 8 ms 5472 KB Output is correct
22 Correct 8 ms 5472 KB Output is correct
23 Correct 9 ms 5472 KB Output is correct
24 Correct 8 ms 5480 KB Output is correct
25 Correct 9 ms 5472 KB Output is correct
26 Correct 9 ms 5496 KB Output is correct
27 Correct 9 ms 5472 KB Output is correct
28 Correct 10 ms 5472 KB Output is correct
29 Correct 11 ms 5492 KB Output is correct
30 Correct 13 ms 5492 KB Output is correct
31 Correct 9 ms 5496 KB Output is correct
32 Correct 10 ms 5504 KB Output is correct
33 Correct 14 ms 5732 KB Output is correct
34 Correct 14 ms 5780 KB Output is correct
35 Correct 30 ms 5776 KB Output is correct
36 Correct 14 ms 5788 KB Output is correct
37 Correct 15 ms 5784 KB Output is correct
38 Correct 33 ms 5772 KB Output is correct
39 Correct 16 ms 5788 KB Output is correct
40 Correct 16 ms 5796 KB Output is correct
41 Correct 49 ms 5780 KB Output is correct
42 Correct 17 ms 5868 KB Output is correct
43 Correct 17 ms 5928 KB Output is correct
44 Correct 52 ms 5880 KB Output is correct
45 Correct 19 ms 5896 KB Output is correct
46 Correct 18 ms 5888 KB Output is correct
47 Correct 55 ms 5916 KB Output is correct
48 Correct 19 ms 5976 KB Output is correct
49 Correct 19 ms 5924 KB Output is correct
50 Correct 67 ms 5916 KB Output is correct
51 Correct 21 ms 5984 KB Output is correct
52 Correct 21 ms 5976 KB Output is correct
53 Correct 80 ms 5956 KB Output is correct
54 Correct 21 ms 6016 KB Output is correct
55 Correct 21 ms 5980 KB Output is correct
56 Correct 95 ms 5992 KB Output is correct
57 Correct 22 ms 6056 KB Output is correct
58 Correct 22 ms 6104 KB Output is correct
59 Correct 101 ms 6020 KB Output is correct
60 Correct 31 ms 6064 KB Output is correct
61 Correct 24 ms 6088 KB Output is correct
62 Correct 119 ms 6132 KB Output is correct
63 Correct 94 ms 6068 KB Output is correct
64 Correct 169 ms 6052 KB Output is correct
65 Correct 128 ms 6028 KB Output is correct
66 Correct 108 ms 6064 KB Output is correct
67 Correct 104 ms 6060 KB Output is correct
68 Correct 49 ms 6096 KB Output is correct
69 Correct 49 ms 6100 KB Output is correct
70 Correct 40 ms 6076 KB Output is correct
71 Correct 44 ms 6100 KB Output is correct
72 Incorrect 35 ms 6116 KB Output isn't correct
73 Incorrect 47 ms 6120 KB Output isn't correct
74 Correct 75 ms 6192 KB Output is correct
75 Correct 72 ms 6084 KB Output is correct
76 Correct 65 ms 6108 KB Output is correct
77 Correct 64 ms 6096 KB Output is correct
78 Correct 76 ms 6092 KB Output is correct
79 Correct 51 ms 6108 KB Output is correct
80 Correct 61 ms 6092 KB Output is correct
81 Correct 70 ms 6084 KB Output is correct
82 Correct 63 ms 6124 KB Output is correct
83 Correct 78 ms 6088 KB Output is correct
84 Correct 70 ms 6096 KB Output is correct
85 Correct 77 ms 6072 KB Output is correct
86 Correct 82 ms 6112 KB Output is correct
87 Correct 77 ms 6084 KB Output is correct
88 Correct 79 ms 6100 KB Output is correct
89 Correct 81 ms 6064 KB Output is correct
90 Correct 83 ms 6088 KB Output is correct
91 Correct 83 ms 6092 KB Output is correct
92 Correct 92 ms 6076 KB Output is correct