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  1. //Bismillahir Rahmanir Rahim
  2. //Shariful Islam(1804011)
  3. //Chittagong University of Engineering & Technology
  4. #include<bits/stdc++.h>
  5. #define pb push_back
  6. #define fin(i,arr,n) for(i=0;i<n;i++)cin>>arr[i]
  7. #define fout(i,arr,n) for(i=0;i<n;i++)cout<<arr[i]<<" "
  8. #define inf 9223372036854775807
  9. #define vi vector<ll>
  10. #define init ll n,m,a,i,b,j,k,t,x,y,z,tc,u,v,w
  11. #define f(i,n) for(i=0;i<n;i++)
  12. #define mem(a,x) memset(a,x,sizeof(a))
  13. #define sortt(v)  sort(v.begin(),v.end())
  14. #define sitr(itr,st) for(itr=st.begin();itr!=st.end();itr++)
  15. #define pr pair<ll,ll>
  16. #define pi acos(-1.00)
  17. #define mod 1000000007
  18. using namespace std;
  19. typedef long long ll;
  20. struct node
  21. {
  22.     bool endmark;
  23.     node* next[3];
  24.     node()
  25.     {
  26.         endmark=0;
  27.         ll i;
  28.         f(i,3)
  29.         next[i]=NULL;
  30.     }
  31. }*root;
  32.  
  33. void insert(string str)
  34. {
  35.    ll sz=str.size();
  36.    node* curr=root;
  37.    ll i;
  38.    f(i,sz)
  39.    {
  40.        ll id=str[i]-'0';
  41.        if(curr->next[id]==NULL)
  42.         curr->next[id]=new node();
  43.        curr=curr->next[id];
  44.  
  45.  
  46.    }
  47.    curr->endmark=1;
  48.  
  49. }
  50. ll query(string str)
  51. {
  52.     ll sz=str.size();
  53.     node* curr=root;
  54.     string tt="";
  55.     ll i;
  56.     f(i,sz)
  57.     {
  58.         ll id=str[i]-'0';
  59.         if(curr->next[!id])
  60.             tt+=char('0'+!id),curr=curr->next[!id];
  61.         else if(curr->next[id])
  62.         {
  63.             tt+=char('0'+id),curr=curr->next[id];
  64.         }
  65.     else tt+=str[i];
  66.     }
  67.     bitset<40>bit(tt);
  68.     return bit.to_ulong();
  69. }
  70. string binary(ll n)
  71. {
  72.     ll u;
  73.     string tt="";
  74.     while(n)
  75.     {
  76.         u=n%2;
  77.         if(u==0)
  78.             tt="0"+tt;
  79.         else tt="1"+tt;
  80.         n/=2;
  81.     }
  82.     ll sz=tt.size();
  83.     for(ll i=0;i<40-sz;i++)
  84.         tt="0"+tt;
  85.     return tt;
  86. }
  87. int main()
  88. {   ios_base::sync_with_stdio(false);  cin.tie(NULL); cout.tie(NULL);
  89.       //freopen("read.txt","r",stdin);
  90.       //freopen("write.txt","w",stdout);
  91.       init;
  92.       root=new node();
  93.       ll arr[100005],pre1[100005],pre2[100005],ans=0;
  94.       //cout<<binary(12)<<endl;
  95.       cin>>n;
  96.       f(i,n)
  97.       {
  98.           cin>>arr[i];
  99.           if(i==0)
  100.           pre1[i]=arr[i];
  101.           else pre1[i]=pre1[i-1]^arr[i];
  102.           ans=max(ans,pre1[i]);
  103.  
  104.       }
  105.       for(i=n-1;i>=0;i--)
  106.       {
  107.           if(i==n-1)
  108.             pre2[i]=arr[i];
  109.           else pre2[i]=pre2[i+1]^arr[i];
  110.           ans=max(ans,pre2[i]);
  111.       }
  112.       for(i=n-2;i>=0;i--)
  113.       {
  114.           insert(binary(pre2[i+1]));
  115.           ans=max(ans,pre1[i]^query(binary(pre1[i])));
  116.       }
  117.       cout<<ans<<endl;
  118.  
  119.  
  120.  
  121.  
  122.  
  123.  
  124. }
  125.  
  126.  
  127.  
  128.  
Success #stdin #stdout 0s 4580KB
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https://ideone.com/uO7jxh
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
secret

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