Submission #931002

#	Time	Username	Problem	Language	Result	Execution time	Memory
931002		kigash	XOR Sum (info1cup17_xorsum)	C++17	100 / 100	1062 ms	90628 KiB

xorsum

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

// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")

using ll = long long;
using ld = long double;
#define pb push_back
#define ff first
#define ss second
#define sz(x) (ll)(x).size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
void IOIGold2024_In_Shaa_Allah() { ios_base::sync_with_stdio(false); cin.tie(NULL); }
ll binmul(ll a, ll b, ll c) { ll res = 0; while(b) { if(b&1) (res += a) %= c; (a += a) %= c; b >>= 1; } return res; }
ll binpow(ll a, ll b, ll c) { ll res = 1; while(b) { if(b&1) (res *= a) %= c; (a *= a) %= c; b >>= 1; } return res; }
template<typename T> T gcd(T a, T b) { if(b==0) return a; return gcd(b, a%b); }
template<typename T> T lcm(T a, T b) { return a/gcd(a, b)*b; }
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ld rnd() { return rng()%INT_MAX*1.0/INT_MAX; }

const ll inf = 1e18+7, MX = LLONG_MAX, MN = LLONG_MIN;
const ll mod = 1e9+7, N = 1e6+5;
ll a[N];

void kigash() {
    ll n;
    cin>>n;
    vector<pair<ll, ll>> c0, c1;
    for(ll i=1; i<=n; i++) {
        cin>>a[i];
        if(a[i]&1) c1.pb({0, i});
        else c0.pb({0, i});
    }
    ll ans = 0;
    for(ll k=0; k<30; k++) {
        // cout<<k<<":\nc0:\n";
        // for(auto [x, id]: c0) cout<<x<<" "<<id<<"\n";
        // cout<<"c1:\n";
        // for(auto [x, id]: c1) cout<<x<<" "<<id<<"\n";
        ll j = 0, val = (1ll<<k), cnt = 0;
        for(ll i=sz(c0)-1; i>=0; i--) {
            ll x = c0[i].ff, id = c0[i].ss;
            while(j<sz(c0) && c0[j].ff+x<val) j++;
            if(j>i) break;
            cnt += sz(c0)-j-(sz(c0)-i-1);
        }
        j = 0;
        for(ll i=sz(c1)-1; i>=0; i--) {
            ll x = c1[i].ff, id = c1[i].ss;
            while(j<sz(c1) && c1[j].ff+x<val) j++;
            if(j>i) break;
            cnt += sz(c1)-j-(sz(c1)-i-1);
        }
        // cnt /= 2;
        // cout<<cnt<<" ";
        j = sz(c1)-1;
        for(ll i=0; i<sz(c0); i++) {
            ll x = c0[i].ff, id = c0[i].ss;
            while(j>-1 && c1[j].ff+x>=val) j--;
            cnt += j+1;
        }
        // cout<<cnt<<"\n\n";
        if(cnt&1) ans += val;
        vector<pair<ll, ll>> C0, C1;
        for(ll i=0; i<sz(c0); i++) {
            ll x = c0[i].ff, id = c0[i].ss;
            if(a[id]&(val*2)) C1.pb({x, id});
            else C0.pb({x, id});
        }
        for(ll i=0; i<sz(c1); i++) {
            ll x = c1[i].ff, id = c1[i].ss;
            if(a[id]&(val*2)) C1.pb({x+val, id});
            else C0.pb({x+val, id});
        }
        c0 = C0, c1 = C1;
    }
    cout<<ans<<"\n";
    return;
}

signed main(/*Kigash Amir*/) {
    // freopen("");
    IOIGold2024_In_Shaa_Allah();
    ll tt = 1;
    // cin>>tt;
    for(ll i=1; i<=tt; i++) {
        kigash();
    }
}

Compilation message (stderr)

xorsum.cpp: In function 'void kigash()':
xorsum.cpp:47:30: warning: unused variable 'id' [-Wunused-variable]
   47 |             ll x = c0[i].ff, id = c0[i].ss;
      |                              ^~
xorsum.cpp:54:30: warning: unused variable 'id' [-Wunused-variable]
   54 |             ll x = c1[i].ff, id = c1[i].ss;
      |                              ^~
xorsum.cpp:63:30: warning: unused variable 'id' [-Wunused-variable]
   63 |             ll x = c0[i].ff, id = c0[i].ss;
      |                              ^~
xorsum.cpp: In function 'void freopen(std::string)':
xorsum.cpp:17:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 | void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
      |                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:17:73: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 | void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
      |                                                                  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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