Cod sursa(job #792152)

Utilizator pantaniMarco Pantani pantani Data 26 septembrie 2012 16:58:02
Problema Xor Max Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.81 kb
#include<stdio.h>
#include<assert.h>

#include <algorithm>
using namespace std;

#define x first
#define y second
#define BIT 21

struct Trie
{
    int val;
    Trie *st,*dr;

    Trie()
    {
        st=dr=NULL;
    }
};

int n,x,y,sol,a[100100];
Trie r;

void add(int t, int index)
{
    int i;
    Trie *point=&r;
    for(i=BIT;i>=0;--i) {
        if(t&(1<<i))
        {
            if(point->dr==NULL)
                point->dr=new Trie;
            point=point->dr;
        }
        else
        {
            if(point->st==NULL)
                point->st=new Trie;
            point=point->st;
        }
        point->val = index;
    }
}

pair<int, int> query(int t)
{
    Trie *point=&r;
    int sol=0, index = -1;
    for(int i=BIT;i>=0;--i)
    {
        sol*=2;
        if(t&(1<<i))
        {
            if(point->st)
            {
                sol+=1;
                point=point->st;
            }
            else
                point=point->dr;
        }
        else
        {
            if(point->dr)
            {
                sol+=1;
                point=point->dr;
            }
            else
                point=point->st;
        }
        index = point->val;
    }
    return make_pair(sol, index);
}

void read()
{
    assert(freopen("xormax.in","r",stdin)!=NULL);
    int i;
    scanf("%d",&n);
    for(i=1;i<=n;++i)
        scanf("%d",&a[i]);
}

void solve()
{
    int i;
    pair<int, int> z;
    add(0, 0);
    for(i=1;i<=n;++i)
        a[i]=a[i-1]^a[i];
    for(i=1;i<=n;++i)
    {
        z=query(a[i]);
        if(z.x>sol) {
            sol=z.x;
            x = z.y;
            y = i;
        }
        add(a[i], i);
    }
}

void write()
{
    assert(freopen("xormax.out","w",stdout)!=NULL);
    printf("%d %d %d", sol, x+1, y);
}

int main()
{
    read();
    solve();
    write();
    return 0;
}