Submission #1029249

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029249		TrinhKhanhDung	XOR (IZhO12_xor)	C++14	100 / 100	108 ms	121680 KiB

xor

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1019972207)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int lim = 1e7 + 10;

struct Node{
    int childs[2];
    int val;

    Node(){
        memset(childs, -1, sizeof childs);
        val = INF;
    }
} nodes[lim];
int timer;

const int MAX = 3e5 + 10;

int N, X;
int a[MAX], pre[MAX];

void addKey(int num, int id){
    int cur = 0;
    for(int i=30; i>=0; i--){
        int bit = BIT(num, i);
        if(nodes[cur].childs[bit] == -1){
            nodes[cur].childs[bit] = ++timer;
        }
        cur = nodes[cur].childs[bit];
        minimize(nodes[cur].val, id);
    }
}

int getVal(int num){
    int cur = 0, ans = INF, val = 0;
    for(int i=30; i>=0; i--){
        if(cur == -1) break;
        int bit = BIT(num, i);
        if(val + MASK(i) >= X){
            if(nodes[cur].childs[!bit] != -1){
                minimize(ans, nodes[nodes[cur].childs[!bit]].val);
            }
            cur = nodes[cur].childs[bit];
        }
        else{
            cur = nodes[cur].childs[!bit];
            val += MASK(i);
        }
    }
    return ans;
}

void solve(){
    cin >> N >> X;
    for(int i=1; i<=N; i++){
        cin >> a[i];
    }

    addKey(0, 0);
    int ans = 0, pos;
    for(int i=1; i<=N; i++){
        pre[i] = pre[i - 1] ^ a[i];
        int p = getVal(pre[i]);
        if(maximize(ans, i - p)){
            pos = p + 1;
        }
        addKey(pre[i], i);
    }
    cout << pos << ' ' << ans << '\n';
}

signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
   // freopen("task.inp", "r", stdin);
   // freopen("task.out", "w", stdout);

    solve();

    return 0;
}

Compilation message (stderr)

xor.cpp: In function 'void solve()':
xor.cpp:95:20: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   95 |     cout << pos << ' ' << ans << '\n';
      |                    ^~~

• Subtask 1: 100 / 100