#include <iostream>
#include <math.h>
#include <cstdlib>
using namespace std;
int main()
{
int t1, t2, roznica, liczba;
cin >> t1;
if(t1 > pow(10, 5) || t1 < 1)
{
return 0;
}
int *wsk = new int[t1];
for(int i = 0; i < t1; i++)
{
tu:
cin >> liczba;
if(liczba > pow(10, 9) || liczba < 0)
{
goto tu;
}
wsk[i] = liczba;
}
cin >> t2;
if(t2 > pow(10, 5) || t2 < 1)
{
return 0;
}
int *wsk2 = new int[t2];
for(int j = 0; j < t2; j++)
{
tam:
cin >> liczba;
if(liczba > pow(10, 9) || liczba < 0)
{
goto tam;
}
wsk2[j] = liczba;
}
roznica = wsk[0] - wsk2[0];
abs(roznica);
for(int z = 0; z < t1; z++)
{
for(int m = 0; m < t2; m++)
{
if(abs(wsk[z] - wsk2[m]) < roznica)
{
roznica = abs(wsk[z] - wsk2[m]);
}
}
}
cout << roznica << endl;
delete [] wsk;
delete [] wsk2;
return 0;
}
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