Submission #730066

#	Time	Username	Problem	Language	Result	Execution time	Memory
730066		fdnfksd	XOR Sum (info1cup17_xorsum)	C++14	100 / 100	675 ms	44456 KiB

xorsum

#include<bits/stdc++.h>
#define TASKNAME "codeforce"
#define pb push_back
#define pli pair<int,int>
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=2e6;
const ll inf=1e18;
const ll mod=1e9+7;
vector<ll> cc;
ll n;
ll a[maxN],b[maxN];
ll g(ll i,ll j)
{
    return i&((1<<(j+1))-1);
}
ll get(ll j)
{
    ll cnt=0;
    ll sum=0;
    for(ll i=1;i<=n;i++)
    {
        ll x=a[i]>>j&1;
        cnt+=x;
        cnt%=2;
        sum+=(cnt+x*(i));
        sum%=2;
    }
    cnt=0;
    ll k=0;
    for(int i=cc.size()-1;i>=0;i--)
    {
        while(k<cc.size()&&g(cc[k],j-1)+g(cc[i],j-1)>=(1<<j)) k++;
        ll x=k;
        if(g(cc[i],j-1)*2>=(1<<j)) x++;
        cnt+=x;
    }
    cnt/=2;
    sum+=cnt;
    sum%=2;
    return sum;
}
void upd(ll j)
{
    vector<ll> x,y;
    for(int i=0;i<cc.size();i++)
    {
        if(cc[i]>>j&1) x.pb(cc[i]);
        else y.pb(cc[i]);
    }
    for(int i=0;i<x.size();i++)
    {
        cc[i]=x[i];
    }
    for(int i=x.size();i<x.size()+y.size();i++)
    {
        cc[i]=y[i-x.size()];
    }
}
void solve()
{
    cin >> n;
    cc.resize(n);
    for(int i=1;i<=n;i++) cin >> a[i],cc[i-1]=(a[i]);
    ll ans=0;
    for(int j=0;j<=29;j++)
    {
        ans+=get(j)<<j;
        upd(j);
    }
    //cout << cc.size()<<'\n';
    //for(auto zz:cc) cout << zz<<' ';
    cout << ans;
}
int main()
{
    fastio
    //freopen(TASKNAME".INP","r",stdin);
    //freopen(TASKNAME".OUT","w",stdout);
    solve();
}

Compilation message (stderr)

xorsum.cpp: In function 'll get(ll)':
xorsum.cpp:36:16: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         while(k<cc.size()&&g(cc[k],j-1)+g(cc[i],j-1)>=(1<<j)) k++;
      |               ~^~~~~~~~~~
xorsum.cpp: In function 'void upd(ll)':
xorsum.cpp:49:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |     for(int i=0;i<cc.size();i++)
      |                 ~^~~~~~~~~~
xorsum.cpp:54:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |     for(int i=0;i<x.size();i++)
      |                 ~^~~~~~~~~
xorsum.cpp:58:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |     for(int i=x.size();i<x.size()+y.size();i++)
      |                        ~^~~~~~~~~~~~~~~~~~

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