oj.uz

Submission #58113

# Submission time Handle Problem Language Result Execution time Memory
58113 2018-07-16T21:15:47 Z Benq XOR (IZhO12_xor) C++14
100 / 100
 170 ms 29392 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 250001;

int n,x,cum[MX];

template<int MX> struct tri {
    static const int MXBIT = 30;
    int trie[MX][2], mn[MX], nex = 0; // easily changed to character
    
    void ins(int ind, int a = 1) { // insert or delete
        int x = cum[ind];
        int cur = 0;
        F0Rd(i,MXBIT) {
            int t = (x&(1LL<<i))>>i;
            if (!trie[cur][t]) {
                trie[cur][t] = ++nex;
                mn[nex] = ind;
                trie[nex][0] = trie[nex][1] = 0;
            }
            cur = trie[cur][t];
        }
    }
    
    int test(int num, int cur = 0, int cbit = 29, int z = 0) {
        if (cur == 0 && cbit != 29) return MOD;
        if (z || cbit == -1) return mn[cur];
        
        int b = (num>>cbit)&1;
        
        if (b) num ^= 1<<cbit;
        if (!(x&(1<<cbit))) {
            int ret = MOD;
            ret = min(ret,test(num,trie[cur][b],cbit-1,0));
            ret = min(ret,test(num^(1<<cbit),trie[cur][b^1],cbit-1,1));
            return ret;
        } else {
            return test(num^(1<<cbit),trie[cur][b^1],cbit-1,0);
        }
    }
};

tri<10000000> t;

pi ans;

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n >> x;
    FOR(i,1,n+1) {
        cin >> cum[i];
        cum[i] ^= cum[i-1];
    }
    FOR(i,1,n+1) {
        t.ins(i-1);
        int x = t.test(cum[i]);
        ans = max(ans,{i-x,-(x+1)});
    }
    cout << -ans.s << " " << ans.f;
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 428 KB Output is correct
4 Correct 3 ms 560 KB Output is correct
5 Correct 7 ms 1392 KB Output is correct
6 Correct 9 ms 1552 KB Output is correct
7 Correct 9 ms 1732 KB Output is correct
8 Correct 10 ms 1936 KB Output is correct
9 Correct 43 ms 11584 KB Output is correct
10 Correct 45 ms 11820 KB Output is correct
11 Correct 46 ms 11820 KB Output is correct
12 Correct 44 ms 11820 KB Output is correct
13 Correct 44 ms 11820 KB Output is correct
14 Correct 43 ms 11820 KB Output is correct
15 Correct 43 ms 11820 KB Output is correct
16 Correct 43 ms 11820 KB Output is correct
17 Correct 122 ms 23420 KB Output is correct
18 Correct 133 ms 25324 KB Output is correct
19 Correct 126 ms 27304 KB Output is correct
20 Correct 170 ms 29392 KB Output is correct