Submission #756037

# Submission time Handle Problem Language Result Execution time Memory
756037 2023-06-11T00:56:14 Z NK_ XOR (IZhO12_xor) C++17
100 / 100
166 ms 128460 KB
#include <bits/stdc++.h>

using namespace std;

/////////////////////// MACROS ////////////////////////////////////////////
using ll = long long;
using ld = long double;
using db = double;
using str = string;

using pi = pair<int,int>;
using pl = pair<ll,ll>;

using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<str>;
using vc = vector<char>;
using vpi = vector<pi>;
using vpl = vector<pl>;

#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT, size_t SZ> using AR = array<T,SZ>;
tcTU> using PR = pair<T,U>;
tcTU> using umap = unordered_map<T, U>;
tcT> using uset = unordered_set<T>;
tcT> using mset = multiset<T>;

#define mp make_pair
#define f first
#define s second

#define sz(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define ppb pop_back()
#define ppf pop_front()
#define pb push_back
#define eb emplace_back
#define pf push_front

#define lb lower_bound
#define ub upper_bound

// LOOPS
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_, a)
#define each(a,x) for (auto& a: x)

/////////////////////// IMPORANT VARS /////////////////////////////////////

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INFL = ll(3e18)+10;
const int INF = int(1e9)+10;
const ld PI = acos((ld)-1);
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1};
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;
tcT> using pql = priority_queue<T,vector<T>,less<T>>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define nl '\n'

constexpr int pct(int x) { return __builtin_popcount(x); } // # of bits set
constexpr int bits(int x) { 
	return x == 0 ? 0 : 31-__builtin_clz(x); }
constexpr int p2(int x) { return 1<<x; }
constexpr int msk2(int x) { return p2(x)-1; }
 
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
 
tcT> bool ckmin(T& a, const T& b) {
	return b < a ? a = b, 1 : 0; } // set a = min(a,b)
tcT> bool ckmax(T& a, const T& b) {
	return a < b ? a = b, 1 : 0; }
 
tcTU> T fstTrue(T lo, T hi, U f) {
	hi ++; assert(lo <= hi); // assuming f is increasing
	while (lo < hi) { // find first index such that f is true 
		T mid = lo+(hi-lo)/2;
		f(mid) ? hi = mid : lo = mid+1; 
	} 
	return lo;
}
tcTU> T lstTrue(T lo, T hi, U f) {
	lo --; assert(lo <= hi); // assuming f is decreasing
	while (lo < hi) { // find first index such that f is true 
		T mid = lo+(hi-lo+1)/2;
		f(mid) ? lo = mid : hi = mid-1;
	} 
	return lo;
}
tcT> void remDup(vector<T>& v) { // sort and remove duplicates
	sort(all(v)); v.erase(unique(all(v)),end(v)); }
tcTU> void erase(T& t, const U& u) { // don't erase
	auto it = t.find(u); assert(it != end(t));
	t.erase(it); } // element that doesn't exist from (multi)set


// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;

// tcT> using iset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; 
// #define ook order_of_key
// #define fbo find_by_order

// struct chash { 
// 	const uint64_t C = ll(2e18*PI)+71;
// 	const int RANDOM = rng();
// 	ll operator()(ll x) const {
// 		return __builtin_bswap64((x^RANDOM)*C); }
// };
// template<class K,class V> using um = unordered_map<K,V,chash>;
// template<class K,class V> using ht = gp_hash_table<K,V,chash>;
// template<class K,class V> V get(ht<K,V>& u, K x) {
// 	auto it = u.find(x); return it == end(u) ? 0 : it->s; }

/////////////////////// OUPUT /////////////////////////////////////////////
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) {
	#ifdef LOCAL
		return b ? "true" : "false";
	#else
		return ts((int)b);
	#endif
}
tcTU> str ts(pair<T,U> p) {
	#ifdef LOCAL
		return "("+ts(p.f)+", "+ts(p.s)+")";
	#else
		return ts(p.f)+" "+ts(p.s);
	#endif
}

tcTU> str ts(V<pair<T, U>> v) {
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;
	#endif
}

tcT> str ts(T v) {
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;

	#endif
}

///////////////////////// DEBUG ///////////////////////////////////////////
#define tcTUU tcT, class ...U
void DBG() { cerr << "]" << "\e[0m" << endl; }
tcTUU> void DBG(const T& t, const U&... u) {
	cerr << ts(t); if (sizeof...(u)) cerr << ", ";
	DBG(u...); }
#ifdef LOCAL
	#define dbg(...) cerr << "\e[1m" << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
	#define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
		 << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
	#define dbg(...) 0
	#define chk(...) 0
#endif	

///////////////////////// FILE I/O ////////////////////////////////////////
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setPrec() { cout << fixed << setprecision(15); }
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void setIO(str s = "") {
	unsyncIO(); setPrec();
	#ifndef LOCAL	
		if (sz(s)) setIn(s+".in"), setOut(s+".out"); // for USACO
	#endif
}

///////////////////////// TEMPLATE ABOVE //////////////////////////////////

// REMEMBER
// - Don't Focus On Only One Approach
// - Read And Understand Problem Fully
// - Think Of Edges Cases
// - Implement Carefully
// - Always Check For Overflows
// - Reset Global Variables
// - Look At The Bigger Picture
// - Don't Get Discouraged, You Can Pull It Back

template<int SZ, int MXBIT> struct Trie {
	int nex[SZ][2], sz[SZ], ans[SZ], num = 0; // num is last node in trie
	// change 2 to 26 for lowercase letters
	Trie() { memset(nex,0,sizeof nex); memset(sz,0,sizeof sz); F0R(i, SZ) ans[i] = INF; }
	void ins(ll x, int idx) { // insert or delete
		int cur = 0; sz[cur] += 1; ckmin(ans[cur], idx);
		R0F(i,MXBIT) {
			// dbg(cur, ans[cur]);
			int t = (x>>i)&1;
			if (!nex[cur][t]) nex[cur][t] = ++num;
			sz[cur = nex[cur][t]] += 1;
			ckmin(ans[cur], idx);
		}
	}

	int best(ll x, ll y) {
		int cur = 0, ANS = INF;
		bool natural = 0;
		R0F(i,MXBIT) {
			int t = ((x>>i)&1);
			int tx = ((x>>i)&1)^1; int ty = ((y>>i)&1);
			// dbg(x, y, tx, ty);
			if (!nex[cur][tx] || !sz[nex[cur][tx]]) tx ^= 1;
			// dbg(x, y, tx, ty);

			if ((tx^t) < ty) break;
			if ((tx^t) > ty) ckmin(ANS, ans[nex[cur][tx]]), tx ^= 1;

			if (!nex[cur][tx] || !sz[nex[cur][tx]]) break;
			cur = nex[cur][tx];
			if (i == 0) natural = 1;
		}

		if (natural) ckmin(ANS, ans[cur]);

		return ANS;
	}

	ll compute(ll x) { // compute max xor
		if (!sz[0]) return -INF; // no elements in trie
		int cur = 0;
		R0F(i,MXBIT) {
			int t = ((x>>i)&1); // add ^1 for min xor
			if (!nex[cur][t] || !sz[nex[cur][t]]) t ^= 1;
			cur = nex[cur][t]; if (t) x ^= 1LL<<i;
		}
		return x;
	}
};

const int nax = 25e4 + 10;
const int bax = 32;
const int tax = bax * nax;
Trie<tax, bax> T;

void solve() {
	int N, X; cin >> N >> X;
	vi A(N); each(x, A) cin >> x;

	int x = 0; T.ins(x, -1);

	int ans = 0, best = -1;
	F0R(i, N) {
		x ^= A[i];
		int pos = T.best(x, X);
		dbg(i, pos);

		if (ckmax(ans, i - pos)) best = pos + 1;

		T.ins(x, i);
	}
	cout << best + 1 << " " << ans << nl;



}

int main() {
	setIO(); 

	int TT = 1;
	// cin >> TT;

	rep(TT) solve();
	
	exit(0-0);
}

Compilation message

xor.cpp: In function 'void solve()':
xor.cpp:194:19: warning: statement has no effect [-Wunused-value]
  194 |  #define dbg(...) 0
      |                   ^
xor.cpp:287:3: note: in expansion of macro 'dbg'
  287 |   dbg(i, pos);
      |   ^~~
xor.cpp: In function 'void setIn(str)':
xor.cpp:201:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  201 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
xor.cpp: In function 'void setOut(str)':
xor.cpp:202:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  202 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 52 ms 125532 KB Output is correct
2 Correct 52 ms 125620 KB Output is correct
3 Correct 50 ms 125460 KB Output is correct
4 Correct 55 ms 125492 KB Output is correct
5 Correct 57 ms 125648 KB Output is correct
6 Correct 60 ms 125784 KB Output is correct
7 Correct 56 ms 125744 KB Output is correct
8 Correct 57 ms 125868 KB Output is correct
9 Correct 86 ms 126648 KB Output is correct
10 Correct 84 ms 126716 KB Output is correct
11 Correct 84 ms 126732 KB Output is correct
12 Correct 96 ms 126612 KB Output is correct
13 Correct 91 ms 126720 KB Output is correct
14 Correct 86 ms 126700 KB Output is correct
15 Correct 84 ms 126720 KB Output is correct
16 Correct 87 ms 126716 KB Output is correct
17 Correct 163 ms 128368 KB Output is correct
18 Correct 156 ms 128460 KB Output is correct
19 Correct 166 ms 128452 KB Output is correct
20 Correct 162 ms 128460 KB Output is correct