Submission #151111

#	Time	Username	Problem	Language	Result	Execution time	Memory
151111		Benq	Trip to the Galapagos Islands (FXCUP4_island)	C++17	100 / 100	594 ms	23984 KiB

island

#include "island.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
 
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 trav(a, x) for (auto& a : x)

#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound

#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rsz resize

const int MOD = 1000000007; // 998244353
const ll INF = 1e18;
const int MX = 100005;
const ld PI = 4*atan((ld)1);

template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }

namespace input {
    template<class T> void re(complex<T>& x);
    template<class T1, class T2> void re(pair<T1,T2>& p);
    template<class T> void re(vector<T>& a);
    template<class T, size_t SZ> void re(array<T,SZ>& a);

    template<class T> void re(T& x) { cin >> x; }
    void re(double& x) { string t; re(t); x = stod(t); }
    void re(ld& x) { string t; re(t); x = stold(t); }
    template<class Arg, class... Args> void re(Arg& first, Args&... rest) { 
        re(first); re(rest...); 
    }

    template<class T> void re(complex<T>& x) { T a,b; re(a,b); x = cd(a,b); }
    template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.f,p.s); }
    template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
    template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
}

using namespace input;

namespace output {
    template<class T1, class T2> void pr(const pair<T1,T2>& x);
    template<class T, size_t SZ> void pr(const array<T,SZ>& x);
    template<class T> void pr(const vector<T>& x);
    template<class T> void pr(const set<T>& x);
    template<class T1, class T2> void pr(const map<T1,T2>& x);

    template<class T> void pr(const T& x) { cout << x; }
    template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) { 
        pr(first); pr(rest...); 
    }

    template<class T1, class T2> void pr(const pair<T1,T2>& x) { 
        pr("{",x.f,", ",x.s,"}"); 
    }
    template<class T> void prContain(const T& x) {
        pr("{");
        bool fst = 1; for (const auto& a: x) pr(!fst?", ":"",a), fst = 0; // const needed for vector<bool>
        pr("}");
    }
    template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
    template<class T> void pr(const vector<T>& x) { prContain(x); }
    template<class T> void pr(const set<T>& x) { prContain(x); }
    template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
    
    void ps() { pr("\n"); }
    template<class Arg> void ps(const Arg& first) { 
        pr(first); ps(); // no space at end of line
    }
    template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) { 
        pr(first," "); ps(rest...); // print w/ spaces
    }
}

using namespace output;

namespace io {
    void setIn(string s) { freopen(s.c_str(),"r",stdin); }
    void setOut(string s) { freopen(s.c_str(),"w",stdout); }
    void setIO(string s = "") {
        ios_base::sync_with_stdio(0); cin.tie(0); // fast I/O
        if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
    }
}

using namespace io;

template<class T> T invGeneral(T a, T b) {
    a %= b; if (a == 0) return b == 1 ? 0 : -1;
    T x = invGeneral(b,a); 
    return x == -1 ? -1 : ((1-(ll)b*x)/a+b)%b;
}

template<class T> struct modular {
    T val; 
    explicit operator T() const { return val; }
    modular() { val = 0; }
    modular(const ll& v) { 
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD;
    }
    
    // friend ostream& operator<<(ostream& os, const modular& a) { return os << a.val; }
    friend void pr(const modular& a) { pr(a.val); }
    friend void re(modular& a) { ll x; re(x); a = modular(x); }
   
    friend bool operator==(const modular& a, const modular& b) { return a.val == b.val; }
    friend bool operator!=(const modular& a, const modular& b) { return !(a == b); }
    friend bool operator<(const modular& a, const modular& b) { return a.val < b.val; }

    modular operator-() const { return modular(-val); }
    modular& operator+=(const modular& m) { if ((val += m.val) >= MOD) val -= MOD; return *this; }
    modular& operator-=(const modular& m) { if ((val -= m.val) < 0) val += MOD; return *this; }
    modular& operator*=(const modular& m) { val = (ll)val*m.val%MOD; return *this; }
    friend modular pow(modular a, ll p) {
        modular ans = 1; for (; p; p /= 2, a *= a) if (p&1) ans *= a;
        return ans;
    }
    friend modular inv(const modular& a) { 
        auto i = invGeneral(a.val,MOD); assert(i != -1);
        return i;
    } // equivalent to return exp(b,MOD-2) if MOD is prime
    modular& operator/=(const modular& m) { return (*this) *= inv(m); }
    
    friend modular operator+(modular a, const modular& b) { return a += b; }
    friend modular operator-(modular a, const modular& b) { return a -= b; }
    friend modular operator*(modular a, const modular& b) { return a *= b; }
    
    friend modular operator/(modular a, const modular& b) { return a /= b; }
};

typedef modular<int> mi;
typedef pair<mi,mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

template<class T, int SZ> struct RMQ {
    constexpr static int level(int x) { return 31-__builtin_clz(x); } // floor(log_2(x))
    int stor[SZ][level(SZ)+1];
    vector<T> v;
    
    int comb(int a, int b) { return v[a] == v[b] ? min(a,b) : (v[a] < v[b] ? a : b); } // index of minimum
    
    void init(const vector<T>& _v) {
        v = _v; F0R(i,sz(v)) stor[i][0] = i; 
        FOR(j,1,level(sz(v))+1) F0R(i,sz(v)-(1<<(j-1))) 
            stor[i][j] = comb(stor[i][j-1],stor[i+(1<<(j-1))][j-1]);
    }
    
    int index(int l, int r) { // get index of min element
        int x = level(r-l+1);
        return comb(stor[l][x],stor[r-(1<<x)+1][x]);
    }
    T query(int l, int r) { return v[index(l,r)]; }
};

pi nex[MX];

template<int SZ> struct DSU {
    int par[SZ], sz[SZ], fst[SZ], lst[SZ];

    DSU() {
        F0R(i,SZ) {
        	par[i] = i, sz[i] = 1;
        	fst[i] = lst[i] = i;
        }
    }

    int get(int x) { // path compression
    	if (par[x] != x) par[x] = get(par[x]);
    	return par[x];
    }

    bool unite(int x, int y, int w) { // union-by-rank
    	if (sz[x] < sz[y]) swap(x,y);
    	sz[x] += sz[y], par[y] = x;
    	nex[lst[x]] = {fst[y],w};
    	lst[x] = lst[y];
    	return 1;
    }
};

const int BLOCK = 320;

RMQ<int,MX> R;
vi ans[MX], pos[MX];
DSU<MX> D;

int getMin(int l, int r) {
	if (l > r) swap(l,r);
	return R.query(l,r-1);
}

void Init(int K, std::vector<int> F, std::vector<int> S, std::vector<int> E){
	int N = F.size(), M = S.size();
	F0R(i,N) nex[i] = {-1,-1};
	F0Rd(i,M) {
		int s = D.get(S[i]), e = D.get(E[i]);
		if (s == e) continue;
		D.unite(s,e,i+1);
	}
	int st = D.fst[D.get(0)];
	/*ps(st);
	F0R(i,N) ps(i,nex[i]);
	exit(0);*/
	vi wei, label;
	F0R(i,N) {
		//ps("CUR",i,st,F[st]);
		pos[F[st]].pb(i);
		label.pb(F[st]);
		if (i != N-1) {
			wei.pb(nex[st].s);
			st = nex[st].f; assert(st != -1);
		}
	}
	// ps("HUH",label,wei);
	R.init(wei);
	F0R(i,K) if (sz(pos[i]) > BLOCK) {
		ans[i] = vi(K,-1);
		int ind = 0;
		F0R(j,N) {
			while (ind < sz(pos[i]) && pos[i][ind] <= j) ind ++;
			if (label[j] == i) continue;
			if (ind > 0) ckmax(ans[i][label[j]],getMin(pos[i][ind-1],j));
			if (ind < sz(pos[i])) ckmax(ans[i][label[j]],getMin(pos[i][ind],j));
		}
	} 
	// ps("HUH",wei);
	// F0R(i,K) ps(i,pos[i]);
	// ToDo
}

int Separate(int A, int B){
	if (sz(pos[A]) < sz(pos[B])) swap(A,B);
	if (sz(pos[A]) > BLOCK) return ans[A][B];
	int ia = 0, ib = 0, res = -1;
	while (ia < sz(pos[A]) && ib < sz(pos[B])) {
		ckmax(res,getMin(pos[A][ia],pos[B][ib]));
		if (pos[A][ia] < pos[B][ib]) ia ++;
		else ib ++;
	}
	return res;
}

Compilation message (stderr)

island.cpp: In function 'void io::setIn(std::__cxx11::string)':
island.cpp:111:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
island.cpp: In function 'void io::setOut(std::__cxx11::string)':
island.cpp:112:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 31 / 31
• Subtask 2: 39 / 39
• Subtask 3: 30 / 30