Submission #1042877

#	Time	Username	Problem	Language	Result	Execution time	Memory
1042877		khanhtb	XOR (IZhO12_xor)	C++14	100 / 100	89 ms	26284 KiB

xor

#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define ld long double
#define pb push_back
#define pf push_front
#define vi vector<ll>
#define vii vector<vi>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define all(a) a.begin(), a.end()
#define fi first
#define se second
using namespace std;
const ll mod = 1e9+7; 
const ll inf = 2e18;
const ll blocksz = 320;
const ll N = 3e5+8;
struct Binary_Trie{
    struct node{
        int child[2], mn;
        node(){
            child[0] = child[1] = -1;
            mn = mod;
        }  
    };
    vector<node> trie = {node()};
    void add(int x, int id){
        int u = 0;
        for(int i = 30; i >= 0; i--){
            bool k = (x>>i&1);
            if(trie[u].child[k] == -1){
                trie[u].child[k] = trie.size();
                trie.pb(node());
            }
            u = trie[u].child[k];
            trie[u].mn = min(trie[u].mn,id);
        }
    }
    int query(int x, int y){
        int ans = mod, u = 0;
        for(int i = 30; i >= 0; i--){
            bool k1 = (x>>i&1), k2 = (y>>i&1);
            if(k1){
                if(trie[u].child[!k2] != -1) u = trie[u].child[!k2];
                else return ans;
            }
            else{
                if(trie[u].child[!k2] != -1) ans = min(ans,trie[trie[u].child[!k2]].mn);
                if(trie[u].child[k2] != -1) u = trie[u].child[k2];
                else return ans;
            }
        }
        ans = min(ans,trie[u].mn);
        return ans;
    }
} trie;
void solve(){
    int n,x;cin >> n >> x;
    int len = 0, ans = 1e9, h = 0;
    trie.add(0,0);
    for(int i = 1; i <= n; i++){
        int a;cin >> a;
        h ^= a;
        int pos = trie.query(x,h);
        if(i-pos > len){
            len = i-pos;
            ans = pos+1;
        }
        trie.add(h,i);
    }
    if(len == 0){
        cout << -1 << " " << -1;
        return;
    }
    cout << ans << " " << len;
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen("test.inp", "r")) {
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }   
    ll T = 1;
    // cin >> T;
    for (ll i = 1; i <= T; i++) {
        solve();
        cout << '\n';
    }
}

Compilation message (stderr)

xor.cpp: In function 'int main()':
xor.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:85:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100