Cod sursa(job #2018067)

Utilizator GoogalAbabei Daniel Googal Data 3 septembrie 2017 13:56:27
Problema Xor Max Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.76 kb
#include <iostream>
#include <fstream>

using namespace std;

ifstream in("xormax.in");
ofstream out("xormax.out");

const int NMAX = 100000;
const int DIM = 1000000;

struct Trie {
  int pos;
  Trie *fii[2];

  Trie() {
    pos = 0;
    fii[0] = fii[1] = NULL;
  }
};

int n, sol = -1;
int poz;
int le, ri, index;
int xs[1 + NMAX];
char buff[DIM];
Trie *root = new Trie;

void read(int &no){
  no = 0;
  while(!isdigit(buff[poz])){
    if(++poz == DIM){
      in.read(buff, DIM);
      poz = 0;
    }
  }

  while(isdigit(buff[poz])){
    no = (no * 10) + (buff[poz] - '0');
    if(++poz == DIM){
      in.read(buff, DIM);
      poz = 0;
    }
  }
}

void add(Trie *node, int s, int ind, int pos) {
  if(pos < 0) {
    node->pos = ind;
    return;
  } else {
    int byte = (s >> pos) & 1;
    if(node->fii[byte] == NULL)
      node->fii[byte] = new Trie();
    add(node->fii[byte], s, ind, pos - 1);
  }
}

int query(Trie *node, int s, int pos) {
  if(pos < 0) {
    return node->pos;
  } else {
    int byte = (s >> pos) & 1;
    if(node->fii[1 - byte] != NULL)
      byte = 1 - byte;
    return query(node->fii[byte], s, pos - 1);
  }
}

void update(int from, int to) {
  int pretender = xs[from] ^ xs[to];
  if(sol < pretender) {
    sol = pretender;
    if(from < to) {
      le = from + 1;
      ri = to;
    } else {
      le = from;
      ri = to;
    }
  }
}

int main()
{
  //in >> n;
  read(n);
  add(root, 0, 0, 21);
  for(int i = 1; i <= n; i++) {
    //in >> xs[i];
    read(xs[i]);
    xs[i] ^= xs[i - 1];
    add(root, xs[i], i, 21);
    index = query(root, xs[i], 21);
    update(index, i);
  }

  out << sol << ' ' << le << ' ' << ri << '\n';
  in.close();
  out.close();
  return 0;
}