Submission #26489

#	Time	Username	Problem	Language	Result	Execution time	Memory
26489		samir_droubi	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1416 ms	838424 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
const int mxn=4005;
char g[mxn][mxn];
int n,m;
 
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
bool check(int x,int y)
{
	return x>=0&&x<n&&y>=0&&y<m&&g[x][y]!='*';
}
char ty;
int c=0;
vector<pair<int,int> >v;
vector<pair<int,int> >vv;
queue<pair<int,int> >q;
void bfs()
{
	while(!q.empty())
	{
		int x=q.front().first;
		int y=q.front().second;
		++c;
		q.pop();
		for(int i=0;i<4;++i)
		{
			int xx=x+dx[i];
			int yy=y+dy[i];
			if(!check(xx,yy))continue;
			if(g[xx][yy]!=ty)
			{
				vv.push_back({xx,yy});
				continue;
			}
			q.push({xx,yy});
			g[xx][yy]='.';
		}
	}
}
int main()
{
	scanf("%d%d",&n,&m);
	int cnt=n*m;
	for(int i=0;i<n;++i)scanf("%s",&g[i]);
	for(int i=0;i<n;++i)
	{
		for(int j=0;j<m;++j)
			if(g[i][j]=='.')
				--cnt;
	}
	v.push_back({0,0});
	int ans=0;
	while(c!=cnt)
	{
		for(int i=0;i<v.size();++i)
		{
			int x=v[i].first;
			int y=v[i].second;
			if(g[x][y]=='.')continue;
			ty=g[x][y];
			g[x][y]='.';
			q.push({x,y});
			bfs();
		}
		v=vv;
		vv.clear();
		++ans;
	}
	printf("%d\n",ans);
	return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:45:38: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[4005]' [-Wformat=]
  for(int i=0;i<n;++i)scanf("%s",&g[i]);
                                      ^
tracks.cpp:56:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<v.size();++i)
                ^
tracks.cpp:43:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
tracks.cpp:45:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=0;i<n;++i)scanf("%s",&g[i]);
                                       ^

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