Submission #143257

#	Time	Username	Problem	Language	Result	Execution time	Memory
143257		Benq	Sky Walking (IOI19_walk)	C++14	100 / 100	2337 ms	463776 KiB

walk

// yamisobadlol

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#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 = 200005;
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> using pqg = priority_queue<T,vector<T>,greater<T>>;

template<class T> T poll(pqg<T>& x) {
    T y = x.top(); x.pop();
    return y;
}

int nex;

template<int SZ> struct Dijkstra {
    ll dist[SZ];
    vpi adj[SZ];

    void addEdge(int A, int B, int C) {
        adj[A].pb({B,C}); adj[B].pb({A,C}); assert(C >= 0);
        // if undirected
    }

    void init(int st) {
        fill_n(dist,SZ,INF);
        pqg<pl> q; q.push({dist[st] = 0,st});
    	while (sz(q)) {
    		auto x = poll(q); if (dist[x.s] < x.f) continue;
    		trav(y,adj[x.s]) if (x.f+y.s < dist[y.f])
    			q.push({dist[y.f] = x.f+y.s,y.f});
    	}
    }
};

Dijkstra<10000000> D;

int N, M, S, G;
vi X,H;
vector<pair<int,vi>> bridge;
vi xx;

void split(int h, vi& z, set<int>& cur, int x) {
	vi Z;
	F0R(i,sz(z)-1) {
		Z.pb(z[i]);
		if (z[i] < x && x < z[i+1]) {
			// ps("HUH",x,H[x],h);
			if (H[x] >= h) Z.pb(x);
			else {
				auto it = cur.lb(x); assert(*it != x);
				if (z[i] < *prev(it)) Z.pb(*prev(it));
				if (*it < z[i+1]) Z.pb(*it);
			}
		}
	}
	Z.pb(z.back());
	swap(z,Z);
}

vpi cor[500000];
map<int,pi> mm;
vector<pair<int,pi>> BRIDGE;

int makeVert(int seg, int x) {
	cor[seg].pb({x,nex++});
	return nex-1;
}

void tri(int seg, int label, int x) {
	auto it = mm.ub(x); if (it == begin(mm) || prev(it)->s.f < x) return;
	int SEG = prev(it)->s.s; if (BRIDGE[SEG].f > H[x]) return;
	int LABEL = makeVert(SEG,x);
	// ps("HUH",seg,label,x,SEG,LABEL);
	D.addEdge(label,LABEL,abs(BRIDGE[seg].f-BRIDGE[SEG].f));
}

void ins(int seg) {
	int l = BRIDGE[seg].s.f, r = BRIDGE[seg].s.s;
	while (1) {
		auto it = mm.lb(l);
		if (it != begin(mm) && prev(it)->s.f >= l) it --;
		if (it == end(mm) || it->f > r) break;
		auto IT = *it; mm.erase(it);
		if (IT.f < l) mm[IT.f] = {l-1,IT.s.s};
		if (IT.s.f > r) mm[r+1] = {IT.s.f,IT.s.s};
	}
	mm[l] = {r,seg};
}

ll min_distance(vi x, vi h, vi l, vi r, vi y, int s, int g) {
	N = sz(x), M = sz(l); if (s > g) swap(s,g);
	X = x, H = h, S = s, G = g;
	F0R(i,sz(l)) bridge.pb({y[i],{l[i],r[i]}});
	sort(bridge.rbegin(),bridge.rend());
	F0R(i,N) xx.pb(i);
	sort(all(xx),[](int a, int b) { return H[a] > H[b]; });
	int ind = 0; set<int> cur;
	/*trav(z,bridge) ps(z);
	ps();
	trav(t,xx) ps("HUH",t,H[t]);*/

	trav(z,bridge) {
		while (ind < sz(xx) && H[xx[ind]] >= z.f) cur.insert(xx[ind++]);
		// ps("??",z.f,cur);
		split(z.f,z.s,cur,S);
		split(z.f,z.s,cur,G);
	}
	trav(z,bridge) F0R(i,sz(z.s)-1) BRIDGE.pb({z.f,{z.s[i],z.s[i+1]}});
	BRIDGE.pb({0,{S,S}}); BRIDGE.pb({0,{G,G}});
	vi special;
	F0R(i,sz(BRIDGE)) {
		cor[i] = {{BRIDGE[i].s.f,2*i},{BRIDGE[i].s.s,2*i+1}};
		if (BRIDGE[i].f == 0) special.pb(2*i);
	}
	nex = 2*sz(BRIDGE);
	F0R(i,sz(BRIDGE)) {
		// ps("HUH",i,BRIDGE[i]);
		tri(i,2*i,BRIDGE[i].s.f);
		tri(i,2*i+1,BRIDGE[i].s.s);
		ins(i);
	}
	mm.clear();
	F0Rd(i,sz(BRIDGE)) {
		tri(i,2*i,BRIDGE[i].s.f);
		tri(i,2*i+1,BRIDGE[i].s.s);
		ins(i);
	}
	// add bridge edges
	F0R(i,sz(BRIDGE)) {
		sort(all(cor[i]));
		F0R(j,sz(cor[i])-1) D.addEdge(cor[i][j].s,cor[i][j+1].s,X[cor[i][j+1].f]-X[cor[i][j].f]);
	}
	D.init(special[0]);
	auto res = D.dist[special[1]]; if (res == INF) res = -1;
	return res;
	// at most M*5 bridges now
	// for each endpoint of every bridge: add to next thing above it or below it
}

/*int main() {
    setIO();
    ps(min_distance({0,3,5,7,10,12,14},
    				{8,7,9,7,6,6,9},
    				{0,0,0,2,2,3,4},
    				{1,2,6,3,6,4,6},
    				{1,6,8,1,7,2,5},
    				1,5));
    ps(min_distance({0,4,5,6,9},
                    {6,6,6,6,6},
                    {3,1,0},
                    {4,3,2},
                    {1,3,6},
                    0,4));
}*/

Compilation message (stderr)

walk.cpp: In function 'void io::setIn(std::__cxx11::string)':
walk.cpp:115:35: 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); }
                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp: In function 'void io::setOut(std::__cxx11::string)':
walk.cpp:116:36: 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: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 18 / 18
• Subtask 5: 43 / 43