Submission #79070

#	Time	Username	Problem	Language	Result	Execution time	Memory
79070		gs14004	Meetings (IOI18_meetings)	C++17	60 / 100	5544 ms	162180 KiB

meetings

#include <bits/stdc++.h>
#include "meetings.h"
using namespace std;
using lint = long long;
using pi = pair<int, int>;
const int MAXN = 750005;
const int MAXT = 2100000;
const int inf = 1e9 + 10;

struct seg{
	int lim;
	pi tree[MAXT];
	void init(vector<int> &v){
		for(lim = 1; lim <= v.size(); lim <<= 1);
		fill(tree, tree + MAXT, pi(-1e9, 0));
		for(int i=0; i<v.size(); i++) tree[i + lim] = pi(v[i], i);
		for(int i=lim-1; i; i--) tree[i] = max(tree[2*i], tree[2*i+1]);
	}
	pi query(int s, int e){
		s += lim;
		e += lim;
		pi ret(-1e9, 0);
		while(s < e){
			if(s%2 == 1) ret = max(ret, tree[s++]);
			if(e%2 == 0) ret = max(ret, tree[e--]);
			s >>= 1;
			e >>= 1;
		}
		if(s == e) ret = max(ret, tree[s]);
		return ret;
	}
}seg;

struct node{
	int s, e, rep; // node range
	int lp, rp; // pointers
	int h; // height
}tr[MAXN];

int ptr, loc[MAXN], parL[MAXN], parR[MAXN];
lint dp[MAXN], lgo[MAXN], rgo[MAXN];
lint L_intercept[MAXN], R_intercept[MAXN];

void make_tree(int s, int e, int v){
	int h, m;
	tie(h, m) = seg.query(s, e);
	loc[m] = v;
	tr[v] = {s, e, m, -1, -1, h};
	if(s <= m - 1){
		ptr++;
		tr[v].lp = ptr;
		make_tree(s, m-1, tr[v].lp);
	}
	if(m + 1 <= e){
		ptr++;
		tr[v].rp = ptr;
		make_tree(m+1, e, tr[v].rp);
	}
}

struct tree_cht{
	struct queries{
		int s, e, x;
	};
	int par[MAXN];
	int a[MAXN]; lint b[MAXN];
	vector<queries> query;
	void build(int n, int *p, node *t, lint *intercept){
		for(int i=1; i<=n; i++){
			par[i] = p[i-1] + 1;
			a[i] = t[i-1].h;
			b[i] = intercept[i-1];
		}
	}
	void add_query(int s, int e, int x){
		query.push_back({s + 1, e + 1, x});
	}
	vector<lint> batch(){
		vector<lint> ret;
		for(auto &i : query){
			lint val = 1e18;
			int s = i.s, e = i.e;
			while(s != e){
				val = min(val, 1ll * a[s] * i.x + b[s]);
				s = par[s];
			}
			ret.push_back(val);
		}
		return ret;
	}
}t1, t2;

vector<lint> minimum_costs(vector<int> H, vector<int> L, vector<int> R){
	int n = H.size();
	int q = L.size();
	seg.init(H);
	make_tree(0, n-1, 0);
	for(int i=ptr; i>=0; i--){
		dp[i] = 1ll * H[tr[i].rep] * (tr[i].e - tr[i].s + 1);
		if(~tr[i].lp){
			dp[i] = min(dp[i], dp[tr[i].lp] + 1ll * H[tr[i].rep] * (tr[i].e - tr[i].rep + 1));
		}
		if(~tr[i].rp){
			dp[i] = min(dp[i], dp[tr[i].rp] + 1ll * H[tr[i].rep] * (tr[i].rep - tr[i].s + 1));
		}
	}
	for(int i=0; i<=ptr; i++){
		if(tr[i].s - 1 >= 0) parR[i] = loc[tr[i].s - 1];
		else parR[i] = -1;
		if(tr[i].e + 1 < n) parL[i] = loc[tr[i].e + 1];
		else parL[i] = -1;
		if(~tr[i].lp){
			lgo[tr[i].lp] = lgo[i] + 1ll * H[tr[i].rep] * (tr[i].e - tr[i].rep + 1);
			rgo[tr[i].lp] = rgo[i];
		}
		if(~tr[i].rp){
			lgo[tr[i].rp] = lgo[i];
			rgo[tr[i].rp] = rgo[i] + 1ll * H[tr[i].rep] * (tr[i].rep - tr[i].s + 1);
		}
		L_intercept[i] = lgo[i] + 1ll * tr[i].h * (tr[i].e + 1);
		if(~tr[i].rp){
			L_intercept[i] = min(L_intercept[i], lgo[i] + 1ll * tr[i].h * (tr[i].rep + 1) + dp[tr[i].rp]);
		}
		R_intercept[i] = rgo[i] + 1ll * tr[i].h * (1 - tr[i].s);
		if(~tr[i].lp){
			R_intercept[i] = min(R_intercept[i], rgo[i] + 1ll * tr[i].h * (1 - tr[i].rep) + dp[tr[i].lp]);
		}
	}
	t1.build(ptr + 1, parL, tr, L_intercept);
	t2.build(ptr + 1, parR, tr, R_intercept);
	vector<pi> lca(q);
	for(int i=0; i<q; i++){
		lca[i] = seg.query(L[i], R[i]);
		t1.add_query(loc[L[i]], loc[lca[i].second], -L[i]);
		t2.add_query(loc[R[i]], loc[lca[i].second], R[i]);
	}
	auto sol1 = t1.batch();
	auto sol2 = t2.batch();
	vector<lint> ret(q);
	for(int i=0; i<q; i++){
		pi p = lca[i];
		int root_num = loc[p.second]; 
		ret[i] = 1ll * (R[i] - L[i] + 1) * p.first;
		if(L[i] < p.second){
			ret[i] = min(ret[i], sol1[i] + 1ll * (R[i] - p.second + 1) * p.first - lgo[tr[root_num].lp]);
		}
		if(p.second < R[i]){
			ret[i] = min(ret[i], sol2[i] + 1ll * (p.second - L[i] + 1) * p.first - rgo[tr[root_num].rp]);
		}
	}
	return ret;
}

Compilation message (stderr)

meetings.cpp: In member function 'void seg::init(std::vector<int>&)':
meetings.cpp:14:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(lim = 1; lim <= v.size(); lim <<= 1);
                ~~~~^~~~~~~~~~~
meetings.cpp:16:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<v.size(); i++) tree[i + lim] = pi(v[i], i);
                ~^~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 15 / 15
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 0 / 40