Submission #924009

#	Time	Username	Problem	Language	Result	Execution time	Memory
924009		Aiperiii	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	823 ms	224772 KiB

tracks

#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N=4e3+5;
char a[N][N];
int d[N][N];
int h,w;

signed main(){
   ios_base::sync_with_stdio();
   cin.tie(0);cout.tie(0);
   cin>>h>>w;
   for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
         cin>>a[i][j];
      }
   }
   vector <int> x={1,-1,0,0},y={0,0,1,-1};
   deque <pair <int,int> > q;
   q.push_back({0,0});
   d[0][0]=1;
   while(!q.empty()){
      pair <int,int> v=q.front();
      q.pop_front();
      int X=v.ff,Y=v.ss;
      for(int i=0;i<4;i++){
         if(X+x[i]>=0 && X+x[i]<h && Y+y[i]>=0 && Y+y[i]<w && a[X+x[i]][Y+y[i]]!='.' && d[X+x[i]][Y+y[i]]==0){
            if(a[X+x[i]][Y+y[i]]==a[X][Y]){
               d[X+x[i]][Y+y[i]]=d[X][Y];
               q.push_front({X+x[i],Y+y[i]});
            }
            else{
               d[X+x[i]][Y+y[i]]=d[X][Y]+1;
               q.push_back({X+x[i],Y+y[i]});
            }
         }
      }
   }
   int ans=0;
   for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
         ans=max(ans,d[i][j]);
      }
   }
   cout<<ans<<"\n";
}
 
/*
FFR.....
.FRRR...
.FFFFF..
..RRRFFR
.....FFF
 */

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