Submission #73092363

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

using i64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    sort(a.begin(), a.end());
    if (n & 1) cout << a[n - 1] << '\n';
    else {
        i64 sum = accumulate(a.begin(), a.end(), 0LL);
        int m = n / 2;
        
        vector<int> ans;
        
        // all 2
        if (sum % m == 0) ans.push_back(sum / m);
    
        // some 1
        int p = n - 1;
        while (p - 1 >= 0 && a[p - 1] == a[p]) p--;
        
        bool ok = true;
        int l = 0, r = p - 1;
        while (l < r) {
            if ((i64) a[l] + a[r] != a[n - 1]) {
                ok = false;
                break;
            }
            l++, r--;
        }
        if (ok && l > r) ans.push_back(a[n - 1]);
        
        int sz = ans.size();
        sort(ans.begin(), ans.end());
        for (int i = 0; i < sz; i++) cout << ans[i] << " \n"[i == sz - 1];
    }
    
    return 0;
}

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