[RUBY] You walk in a spiral in a world where the walls of the cross rise (simulation)

About input / output

All of the following answers use standard input / output, so I need a scoring tool. https://github.com/cielavenir/procon/blob/498c9856ea73bf871c15575e2d21bae7263d1167/hena/tyama_hena_validator.rb Execute with hena_validator.rb hena28.py 28.

However, you can throw in additional questions as they are without using the scoring tool.

Right method (Python / Ruby / C ++)

There is a right method as an algorithm to solve the maze. If there is only one wall (topologically), you have to walk without releasing your right hand to reach the goal. This corresponds to always trying to turn right when viewed from the direction of travel.

CheckiO has a problem with Lantern Festival. The question of answering the number of cells that are currently shining when lanterning. This can also be solved by the right method, so this time I used the Maze class. Therefore, the main language this time is Python. The Ruby version is a port of this.

The C ++ version of CodeIQ this week's algorithm Meet in the maze? .

hena28.py

#!/usr/bin/env python
#http://qiita.com/Nabetani/items/23ebddb44f0234e7fb15
#http://nabetani.sakura.ne.jp/hena/ord28spirwa/

D=( #Right,Up,Left,Down
	(0,1),
	(-1,0),
	(0,-1),
	(1,0),
)
dir=['E','N','W','S']

class Maze:
	def __init__(self,x,y,d,v):
		self.x=x
		self.y=y
		self.d=d
		self.v=v
		self.v[self.y][self.x]='*'
		self.route=[]
		self.route.append((self.x,self.y))
	def move(self):
		d_orig=(self.d+3)%4
		for i in range(4):
			self.d=(d_orig+i)%4
			if self.v[self.y+D[self.d][0]][self.x+D[self.d][1]]=='.': break
		self.y=self.y+D[self.d][0]
		self.x=self.x+D[self.d][1]
		self.v[self.y][self.x]='*'
		self.route.append((self.x,self.y))

if __name__=='__main__':
	import sys
	if sys.version_info[0]>=3: raw_input=input
	Z=100
	try:
		while True:
			line=raw_input().rstrip().split(':')
			n,e,s,w=[int(e) for e in line[0].split(',')]
			days=int(line[1])
			m=[['.']*(Z*2) for i in range(Z*2)]
			m[Z][Z]='*'
			for i in range(n): m[Z-i-1][Z]='*'
			for i in range(e): m[Z][Z+i+1]='*'
			for i in range(s): m[Z+i+1][Z]='*'
			for i in range(w): m[Z][Z-i-1]='*'
			maze=Maze(Z+1,Z-1,0,m)
			for i in range(days+1):maze.move()
			print(dir[maze.d])
			sys.stdout.flush()
	except EOFError:
		pass

hena28.rb

#!/usr/bin/env ruby
#http://qiita.com/Nabetani/items/23ebddb44f0234e7fb15
#http://nabetani.sakura.ne.jp/hena/ord28spirwa/

D=[ #Right,Up,Left,Down
	[0,1],
	[-1,0],
	[0,-1],
	[1,0],
]
dir=['E','N','W','S']

class Maze
	attr_reader :d
	def initialize(x,y,d,v)
		@x=x
		@y=y
		@d=d
		@v=v
		@v[@y][@x]='*'
		@route=[]
		@route<<[@x,@y]
	end
	def move
		d_orig=(@d+3)%4
		4.times{|i|
			@d=(d_orig+i)%4
			break if @v[@y+D[@d][0]][@x+D[@d][1]]=='.'
		}
		@y=@y+D[@d][0]
		@x=@x+D[@d][1]
		@v[@y][@x]='*'
		@route<<[@x,@y]
	end
end

if __FILE__==$0
	Z=100
	while gets
		line=$_.chomp.split(':')
		n,e,s,w=line[0].split(',').map(&:to_i)
		days=line[1].to_i
		m=(Z*2).times.map{['.']*(Z*2)}
		m[Z][Z]='*'
		n.times{|i|m[Z-i-1][Z]='*'}
		e.times{|i|m[Z][Z+i+1]='*'}
		s.times{|i|m[Z+i+1][Z]='*'}
		w.times{|i|m[Z][Z-i-1]='*'}
		maze=Maze.new(Z+1,Z-1,0,m)
		(days+1).times{maze.move}
		puts dir[maze.d]
		STDOUT.flush
	end
end

hena28.cpp

// http://qiita.com/Nabetani/items/23ebddb44f0234e7fb15
// http://nabetani.sakura.ne.jp/hena/ord28spirwa/

#include <cstdio>
#include <string>
#include <vector>
using namespace std;
const int D[4][2]={ //Right,Up,Left,Down
	{0,1},
	{-1,0},
	{0,-1},
	{1,0},
};

class Maze{
	vector<string> &v;
	int x,y,d;
public:
	Maze(int _x,int _y,int _d,vector<string>&_v)
		: x(_x),y(_y),d(_d),v(_v){
			v[y][x]='*';
	}
	void move(){
		int d_orig=(d+3)%4,i=0;
		for(;i<4;i++){
			d=(d_orig+i)%4;
			if(v[y+D[d][0]][x+D[d][1]]=='.')break;
		}
		y=y+D[d][0];
		x=x+D[d][1];
		v[y][x]='*';
	}
	int dir(){return d;}
};

int main(){
	const string dir="ENWS";
	const int Z=100;
	int n,e,s,w;
	long long days;
	for(;scanf("%d,%d,%d,%d:%lld",&n,&e,&s,&w,&days);){
		vector<string> m(Z*2);
		for(int i=0;i<Z*2;i++)m[i]=string(Z*2,'.');
		m[Z][Z]='*';
		for(int i=0;i<n;i++)m[Z-i-1][Z]='*';
		for(int i=0;i<e;i++)m[Z][Z+i+1]='*';
		for(int i=0;i<s;i++)m[Z+i+1][Z]='*';
		for(int i=0;i<w;i++)m[Z][Z-i-1]='*';
		Maze maze(Z+1,Z-1,0,m);
		for(int i=0;i<=days;i++)maze.move();
		printf("%c\n",dir[maze.dir()]);
		fflush(stdout);
	}
}

Another solution for simulation (Ruby)

Usually, when solving a maze, remember the direction you are facing. However, this time, ** no dents appear in the figure **, so it is possible to solve the problem without recording the direction in which it is facing. A strategy to stand a bit and hold the direction of the wall. There is regularity in this "direction". It is easy to understand if you use case-when.

hena28_another.rb

#!/usr/bin/env ruby
#http://qiita.com/Nabetani/items/23ebddb44f0234e7fb15
#http://nabetani.sakura.ne.jp/hena/ord28spirwa/

D=[ #Right,Up,Left,Down
	[0,1],
	[-1,0],
	[0,-1],
	[1,0],
]
dir=['E','N','W','S']

class Maze
	def initialize(x,y,v)
		@x=x
		@y=y
		@v=v
		@v[@y][@x]='*'
	end
	def move
		walls=D.each_with_index.map{|e,i|@v[@y+e[0]][@x+e[1]]=='*' ? 1<<i : 0}.reduce(:+)
		d=case walls
			when 8,8+4,8+6
				0
			when 1,1+8,1+12
				1
			when 2,2+1,2+9
				2
			when 4,4+2,4+3
				3
			else
				raise
		end
		@y=@y+D[d][0]
		@x=@x+D[d][1]
		@v[@y][@x]='*'
		d
	end
end

if __FILE__==$0
	Z=100
	while gets
		line=$_.chomp.split(':')
		n,e,s,w=line[0].split(',').map(&:to_i)
		days=line[1].to_i
		m=(Z*2).times.map{['.']*(Z*2)}
		m[Z][Z]='*'
		n.times{|i|m[Z-i-1][Z]='*'}
		e.times{|i|m[Z][Z+i+1]='*'}
		s.times{|i|m[Z+i+1][Z]='*'}
		w.times{|i|m[Z][Z-i-1]='*'}
		maze=Maze.new(Z+1,Z-1,m)
		days.times{maze.move}
		puts dir[maze.move]
		STDOUT.flush
	end
end