Submission #1176189

#	Time	Username	Problem	Language	Result	Execution time	Memory
1176189		InvMOD	XOR (IZhO12_xor)	C++20	0 / 100	0 ms	320 KiB

xor

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define REV(i, a, b) for(int i = (a); i >= (b); i--)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e5+5;


struct Trie{
    struct Node{
        Node* child[2]; int MnEnd;

        Node(): MnEnd(INT_MAX) {
            for(int i = 0; i < 2; i++){
                child[i] = nullptr;
            }
        }
    };
    typedef Node* pNode;

    pNode root;
    Trie(){
        root = new Node();
    }

    const int lg = 4;
    void addStr(int s, int pos){
        pNode x = root;
        for(int i = lg; i >= 0; i--){
            int c = (s >> i & 1);
            if(x->child[c] == nullptr) x->child[c] = new Node();
            x = x->child[c];
        }
        x->MnEnd = min(x->MnEnd, pos);
    }

    int query(pNode x, int current, int target, int height){
        int MnPos = x->MnEnd;
        if(height < 0) return (current >= target ? MnPos : INT_MAX);
        for(int i = 0; i < 2; i++){
            if(x->child[i] != nullptr){
                int ncurrent = current ^ (i << height);
                MnPos = min(MnPos, query(x->child[i], ncurrent, target, height - 1));
            }
        }
        return MnPos;
    }

    int find_answer(int pref, int target){
        return query(root, pref, target, lg);
    }
};


void solve()
{
    int n,x; cin >> n >> x;

    vector<int> a(n + 1);
    FOR(i, 1, n) cin >> a[i], a[i] ^= a[i - 1];

    Trie trie;

    trie.addStr(0, 0);
    int l = 0, r = 0;

    FOR(i, 1, n){
        int pos = trie.find_answer(a[i], x);
        if(r - l < i - pos){
            l = pos;
            r = i;
        }
        trie.addStr(a[i], i);
    }

    cout << l + 1 <<" " << r - l << "\n";
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

xor.cpp: In function 'int main()':
xor.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
xor.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100