Can't get this

[Kalcor]

I didn't understand exactly what this question said, nor what the editorial said also same goes for the solution e.e, can someone explain to me what exactly is going on in all 3 of these[question, editorial, solution] by relating them to each other? :c thanks alot, here are the references:

Question:
http://codeforces.com/contest/500/problem/B

Editorial part of it:
http://prntscr.com/fkqjg3

Solution code:

#include<bits/stdc++.h>
using namespace std;
int n,per[400],visited[320]={0};
int a[400][400];
char x[10000];
vector<int> v1,v2;
void dfs(int i)
{
	int xs;
	visited[i]=1;
	v1.push_back(i);
	v2.push_back(per[i]);
	
		for(xs=1;xs<=n;xs++)
		{
		if(a[i][xs]==1 && visited[xs]==0)	
				dfs(xs);	
		}
}
int main()
{
	cin >>n;
	for (int i=1;i<=n;i++)
	{
		scanf("%d",&per[i]);
	}
	
	for ( int i=1;i<=n;i++)
	{
        scanf("%s",x);
        for(int j=1;j<=n;j++)
        {
            a[i][j]=x[j-1]-48;
        }
	}	
	for( int i=1;i<=n;i++)
	{
		if(visited[i]==0)
		{
			dfs(i);
			sort(v1.begin(),v1.end());
			sort(v2.begin(),v2.end());
			for(int j=0;j<v1.size();j++)
			{
				per[v1[j]]=v2[j];
			}

	v1.clear();
	v2.clear();
		}
	}
	for(int i=1;i<=n;i++)
	{
		printf("%d ",per[i]);
	}
	printf("\n");	
	return 0;
}