Submission #1146493

#	Time	Username	Problem	Language	Result	Execution time	Memory
1146493		Bilal_Coder	XOR Sum (info1cup17_xorsum)	C++20	45 / 100	413 ms	16436 KiB

xorsum

#include <bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")

using ll = long long;

template<typename... T>
void see(T&... args) { ((cin >> args), ...);}
#define seea(a , x , y) for(int i = x; i < y; i++){cin >> a[i];}
#define sees(s , n) for(int i = 0;i < n; i++){int x; cin >> x; s.insert(x);}
#define seev(v , n) for(int i = 0;i < n; i++){int x; cin >> x; v.push_back(x);}
#define ub(a, x) upper_bound(all(a), x)
#define lb(a, x) lower_bound(all(a), x)
#define rall(x) x.rbegin(), x.rend()
#define all(x) x.begin(), x.end()
#define pii pair<int , int>
#define sz(x) (int)x.size()
#define pq priority_queue
#define vec vector
#define arr array
#define int ll

const ll inf = 1e18;
const int N = 2e5 + 5;

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

void ssolve(vec<int> a , int mx){
    int n = sz(a) ,  mn = inf;
    unordered_map<int , int> mp;
    for (auto x : a)
        mp[x]++ , mn = min(mn , x);
    int ans = 0;
    for (int i = mn; i <= mx << 1; i++){
        for (int j = 0; j <= mx; j++){
            int c = mp[i - j];
            if (c & 1)
                ans ^= i;
        }
    }
    cout << ans << "\n";
    exit(0);
}

void solve() {
    // Code here
    int n;
    see(n);
    vec<int> a;
    int mx = -inf;
    for (int i = 0; i < n; i++){
        int x;see(x);
        mx = max(mx , x) , a.push_back(x);
    }
    if (mx <= 4000)
        ssolve(a , mx);
    int ans = 0;
    for (int i = 0; i < n; i++){
        for (int j = i; j < n; j++)
            ans ^= (a[i] + a[j]);
    }
    cout << ans << "\n";
    return;
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    // setIO("");
        solve();
}

Compilation message (stderr)

xorsum.cpp: In function 'void setIO(std::string)':
xorsum.cpp:31:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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