Submission #142571

#	Time	Username	Problem	Language	Result	Execution time	Memory
142571		nikolapesic2802	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1004 ms	130952 KiB

tracks

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define all(x) x.begin(),x.end()
#define f first
#define s second
using namespace std;

const int N=4001;
char mat[N][N];
int dist[N][N];
vector<int> dx={1,-1,0,0},dy={0,0,1,-1};
int h,w;
bool inside(int x,int y)
{
	return x>=0&&x<h&&y>=0&&y<w&&(mat[x][y]=='F'||mat[x][y]=='R');
}
int main()
{
	 cin >> h >> w;
	 for(int i=0;i<h;i++)
	 	scanf("%s",mat[i]);
	 deque<pair<int,int> > q;
	 q.pb({0,0});
	 dist[0][0]=1;
	 int sol=1;
	 while(q.size())
	 {
 		auto tr=q.front();
 		q.pop_front();
 		sol=max(sol,dist[tr.f][tr.s]);
 		for(int k=0;k<4;k++)
 		{
 			int x=tr.f+dx[k],y=tr.s+dy[k];
 			if(inside(x,y)&&dist[x][y]==0)
 			{
 				if(mat[x][y]==mat[tr.f][tr.s])
 				{
 					dist[x][y]=dist[tr.f][tr.s];
 					q.push_front({x,y});
 				}
 				else
 				{
 					dist[x][y]=dist[tr.f][tr.s]+1;
 					q.push_back({x,y});
 				}
 			}
 		}
 	}
 	printf("%i\n",sol);
}
    

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:22:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%s",mat[i]);
    ~~~~~^~~~~~~~~~~~~

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