Submission #442015

#	Time	Username	Problem	Language	Result	Execution time	Memory
442015		iag99	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	1536 ms	118856 KiB

tracks

#include<bits/stdc++.h>
#define ll long long
#define mod  998244353
using namespace std;
int h,w;
vector<int> dx={1, -1, 0, 0};
vector<int> dy={0, 0, 1, -1};

int depth[4000][4000], ans = 1;
char grid[4000][4000];
bool isfree(int x, int y)
{
	if(x>=0 && x<h && y>=0 && y<w && grid[x][y]!='.')
	{
		return true;
	}
	return false;
}
int main() 
{
	

	cin>>h>>w;
	for(int i=0; i<h; i++)
	{
		for(int j=0; j<w; j++)
		{
			cin>>grid[i][j];
		}
	}
	deque<pair<int,int>> q;
	q.push_back({0,0});
	depth[0][0]=1;
	while(!q.empty())
	{
		pair<int,int> cur=q.front();
		q.pop_front();
		ans=max(ans, depth[cur.first][cur.second]);
		for(int i=0; i<4; i++)
		{
			int x=cur.first+dx[i];
			int y=cur.second+dy[i];
			if(isfree(x,y) && depth[x][y]==0)
			{
				if(grid[x][y]==grid[cur.first][cur.second])
				{
					depth[x][y]=depth[cur.first][cur.second];
					q.push_front({x,y});
				}
				else
				{
					depth[x][y]=depth[cur.first][cur.second]+1;
					q.push_back({x,y});
				}
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70