#include <iostream>
using namespace std;
const int MAX_VALUE = 1000;
int main() {
int fr1[MAX_VALUE + 1] = {0}; // Vector pentru numărarea frecvențelor
int n;
// Citim dimensiunea primului șir
cin >> n;
// Citim elementele primului șir
for (int i = 0; i < n; ++i) {
int currentElement;
cin >> currentElement;
++fr1[currentElement + MAX_VALUE]; // Incrementăm frecvența elementului, cu offset
}
// Citim dimensiunea celui de-al doilea șir
int m = n - 1; // Numărul de elemente în al doilea șir
for (int i = 0; i < m; ++i) {
int currentElement;
cin >> currentElement;
--fr1[currentElement + MAX_VALUE]; // Decrementăm frecvența elementului, cu offset
}
// Găsim elementul lipsă
for (int i = 0; i <= MAX_VALUE * 2; ++i) { // Căutăm în intervalul [-1000, 1000]
if (fr1[i] == 1) { // Elementul cu frecvența 1 este lipsa
cout << (i - MAX_VALUE) << endl; // Afișăm elementul lipsă
break;
}
}
return 0;
}
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