TLX - TROC17A. Firework Festival

You can practice the question [here](https://tlx.toki.id/contests/troc-17/problems/A). Given two arrays A and B, each of size N. Determine whether the sum of A[i]^B[i] for all 1 <= i <= N, is odd or even. Display the output 0 if the sum is even, or 1 if the sum is odd. Input Format ``` N A[1] A[2] ... A[N] B[1] B[2] ... B[N] ``` Sample Input ``` 5 2 4 6 8 2 1 2 3 4 5 ``` Sample Output ``` 0 ``` Constraints ``` 1 <= N <= 100 1 <= A[i], B[i] <= 100 ``` Usually for Problem A, most of the solutions are brute-force. However, if we take the edge case 100, A[0] ^ B[0] + A[1] ^ B[1] + ... + A[99] ^ B[99] where A[i] and B[i] are 100, the overall result would occur overflow. We can notice that this problem is all about parity. The exponent B[i] of A[i] does not change the parity of A[i] ^ B[i]. Hence, we can conclude that ``` even ^ odd -> even even ^ even -> even odd ^ even -> odd odd ^ even -> odd ``` and we know that ``` even + even -> even odd + odd -> even even + odd -> odd ``` Therefore, we can simply sum all the values and check if it is even or odd. ```cpp int main() { int n; cin >> n; vi a(n), b(n); READ(a); READ(b); int sum = 0; REP(i, n) sum += a[i]; OUT((sum & 1)); return 0; } ```