Submission #65651958

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define db double
#define i128 __int128
#define ui unsigned int
#define ull unsigned long long

mt19937 rng_32(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());
const ull X=rng_64();
ull splitmix64(ull x) {
	x^=x<<13;
	x^=x>>7;
	x^=x<<17;
	return x;
}
ull rng(ull x){return splitmix64(x+X);}

const int N=1e3;
ll n,m;
char c[N+10][N+10],ans[N+10][N+10]; 
ll f[N+10][N+10];
queue<pair<int,int> > q; 
int ax[]={-1,0,0,1};
int ay[]={0,-1,1,0};
char op[]={'v','>','<','^'};//may error.

int main(){
	ios::sync_with_stdio(0),cin.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			cin>>c[i][j];
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			if(c[i][j]=='E') f[i][j]=0,q.push(make_pair(i,j));
			else f[i][j]=(ll)1e18;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			ans[i][j]=c[i][j];
	while(!q.empty()){
		int x=q.front().first,y=q.front().second;
		q.pop();
		for(int i=0;i<4;i++){
			int nx=x+ax[i],ny=y+ay[i];
			if(nx<1||nx>n||ny<1||ny>m) continue;
			if(f[nx][ny]!=(ll)1e18) continue;
			if(c[nx][ny]=='#') continue;
			f[nx][ny]=f[x][y]+1;
			ans[nx][ny]=op[i];
			q.push(make_pair(nx,ny));
		}
	}
	for(int i=1;i<=n;i++,cout<<'\n')
		for(int j=1;j<=m;j++)
			cout<<ans[i][j];
	return 0;
}
/*
g++ test.cpp -o test -std=c++14 -O2 -Wall -Wshadow ulimit -s 5120000
./test
*/

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