Submission #1214503

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214503		Ahmed_Solyman	XOR Sum (info1cup17_xorsum)	C++20	0 / 100	48 ms	4420 KiB

xorsum

#include <iostream>
#include <vector>
#include <unordered_map>
#include <algorithm>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    cin >> N;
    vector<int> V(N);
    unordered_map<int, int> freq;

    for (int i = 0; i < N; ++i) {
        cin >> V[i];
        freq[V[i]]++;
    }

    vector<int> S;
    for (const auto& pair : freq) {
        if (pair.second % 2 != 0) {
            S.push_back(pair.first);
        }
    }

    sort(S.begin(), S.end());

    int result = 0;
    int len_S = S.size();

    for (int i = 0; i < len_S; ++i) {
        int x = S[i];
        int cnt = freq[x];
        int pairs = cnt * (cnt + 1) / 2;
        if (pairs % 2 == 1) {
            result ^= (x + x);
        }
        for (int j = i + 1; j < len_S; ++j) {
            int y = S[j];
            result ^= (x + y);
        }
    }

    cout << result << endl;

    return 0;
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 38
• Subtask 5: 0 / 23