Submission #818014

#	Time	Username	Problem	Language	Result	Execution time	Memory
818014		farhan132	XOR Sum (info1cup17_xorsum)	C++17	100 / 100	1033 ms	37680 KiB

xorsum

/***Farhan132***/
#pragma GCC optimize("Ofast,fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>

using namespace std;
 
typedef int ll;
typedef double dd;
typedef pair<ll , ll> ii;
typedef tuple < ll,  ll, ll > tp;
 
#define ff first
#define ss second
#define pb push_back
#define in insert
#define bug printf("**!\n")
#define mem(a , b) memset(a, b ,sizeof(a))
#define front_zero(n) __builtin_clz(n)
#define back_zero(n) __builtin_ctzll(n)
#define total_one(n) __builtin_popcount(n)
#define clean fflush(stdout)
 
const ll mod =  (ll) 998244353;
// const ll mod =  (ll) 1e9 + 7;
const ll inf = numeric_limits<int>::max()-5;
const ll INF = (ll)2e18;
 
ll dx[]={0,1,0,-1};
ll dy[]={1,0,-1,0};
ll dxx[]={0,1,0,-1,1,1,-1,-1};
ll dyy[]={1,0,-1,0,1,-1,1,-1};
 
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
 
template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ll N = 1e6 + 5;

ll a[N];

void solve(){

    ll n; cin >> n;

    ll ans = 0;

    vector < ii > A;

    for(ll i = 1; i <= n; i++) cin >> a[i], A.pb({0, i});

    for(ll b = 0; b < 30; b++){

        vector < ii > B;
        ll now_bit = (1 << b); ll nxt_bit = (1 << (b + 1));

        for(auto [x, i] : A){
            if((a[i] >> b) & 1) continue;
            B.pb({x, i});
        }
        for(auto [x, i] : A){
            if((a[i] >> b) & 1){
                B.pb({x + now_bit, i});
            }
        }
        A = B;
        
        long long cnt = 0;
        
        ll l = n, r = n;
        for(ll i = 0; i < n; i++){
            while(l > 0 && A[l - 1].ff >= now_bit - A[i].ff) l--;
            while(r > 0 && A[r - 1].ff >= nxt_bit - A[i].ff) r--;
            if(r > i){
                cnt += r - max(i, l);
            }
        }
        l = n;
        for(ll i = 0; i < n; i++){
            while(l > 0 && A[l - 1].ff >= now_bit + nxt_bit - A[i].ff) l--;
            cnt += n - max(l, i);
        }
        if(cnt & 1) ans |= (1 << b);
    }

    cout << ans << '\n';



   return;
}

int main() {

    #ifdef LOCAL
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
        auto start_time = clock();
    #else
         // freopen("subsequence.in", "r", stdin);
         // freopen("subsequence.out", "w", stdout); 
         ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    #endif

    //precalc();
 
    ll T = 1, CT = 0; //cin >> T; 
 
    while(T--){
        // cout << "Case #" << ++CT << ": ";
        solve();
    }
    
    #ifdef LOCAL
        auto end_time = clock();
        cerr<< "Execution time: "<<(end_time - start_time)*(int)1e3/CLOCKS_PER_SEC<<" ms\n";
    #endif
 
    return 0;
} 

Compilation message (stderr)

xorsum.cpp:4: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    4 | #pragma GCC optimization ("unroll-loops")
      | 
xorsum.cpp: In function 'int main()':
xorsum.cpp:113:15: warning: unused variable 'CT' [-Wunused-variable]
  113 |     ll T = 1, CT = 0; //cin >> T;
      |               ^~

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