Cod sursa(job #2634882)

Utilizator OvidRata Ovidiu Ovid Data 12 iulie 2020 16:26:16
Problema Xor Max Scor 5
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.75 kb
#include<bits/stdc++.h>
using namespace std;
#define INIT  ios_base :: sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define mp make_pair
#define pb push_back
#define ft first
#define sc second
#define ll long long
#define pii pair<int, int>
#define count_bits __builtin_popcount
ifstream fin("xormax.in"); ofstream fout("xormax.out");
#define cin fin
#define cout fout

int t, n, m, k, a[100010];
int trie[2000010][2][2], l=1;



void trie_insert(int x, int c){
int crd=1;
int pr, ac;
for(int i=20; i>=1; i--){

ac=( ((1<<(i-1) )&x)>0 )?1:0;
pr=( (( 1<<(i))&x)>0 )?1:0;

if(i==1){
    trie[crd][pr][ac]=c; break;
}

if(trie[crd][pr][ac]==0 ){
    trie[crd][pr][ac]=l+1; l++;
    crd=l;
}
else{
 crd=trie[crd][pr][ac];
}

}


}






pii trie_find(int x){
int res=0;
int c=0;

int pr=( (x&(1<<20))?1:0 );
int crd=1;


for(int i=20; i>=1; i--){

    int ac=(( (1<<(i-1) )&x  )>0)?1:0;

    if(trie[crd][pr][ac]==0){
        ac=((ac==1)?0:1);
        if(trie[crd][pr][ac]==0){
            pr=((pr==1)?0:1);
        }
    }
    if(i==20){
        res+=((pr==1)?( (1<<i)):0  );
    }
    crd=trie[crd][pr][ac];
    if(i==1){
        c=crd;
    }
    pr=ac;
    res+=(pr==1)?(1<<(i-1)):0;
}


return mp(res, c);
}






int32_t main(){
INIT
cin>>n;
a[0]=0;
for(int i=1; i<=n; i++){
    cin>>a[i];
    a[i]^=a[i-1];
    trie_insert(a[i], i);
}
trie_insert(0, 0);



int m=0;
int c1=0, c2=0;
for(int i=1; i<=n; i++){
    pii f=trie_find(~a[i]);
    int a2=f.ft;
    if( (a[i]^a2)>m ){
        c1=i; c2=f.sc;
    }
    m=max(a[i]^a2, m);

}
cout<<m<<" "<<min(c1, c2)+1<<" "<<max(c1, c2);




return 0;
}