Submission #79032

#	Time	Username	Problem	Language	Result	Execution time	Memory
79032		gs14004	Meetings (IOI18_meetings)	C++17	60 / 100	5566 ms	119468 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);
	}
}

lint go_left(int pos, int root){
	int L = pos;
	int v = loc[pos];
	root = loc[root];
	lint ret = 1e18;
	while(v != root){
		ret = min(ret, 1ll * tr[v].h * -L + L_intercept[v]);
		v = parL[v];
	}
	ret -= lgo[tr[root].lp];
//	printf("go_left %d -> %d = %lld\n", L, root, ret);
	return ret;
}

lint go_right(int pos, int root){
	int R = pos;
	int v = loc[pos];
	root = loc[root];
	lint ret = 1e18;
	while(v != root){
		ret = min(ret, 1ll * tr[v].h * R + R_intercept[v]);
		v = parR[v];
	}
	ret -= rgo[tr[root].rp];
//	printf("go_right %d -> %d = %lld\n", R, root, ret);
	return ret;
}

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]);
		}
	}
	vector<lint> ret(q);
	for(int i=0; i<q; i++){
		pi p = seg.query(L[i], R[i]);
		ret[i] = min({1ll * (R[i] - L[i] + 1) * p.first, 
			go_left(L[i], p.second) + 1ll * (R[i] - p.second + 1) * p.first, 
			go_right(R[i], p.second) + 1ll * (p.second - L[i] + 1) * p.first});
	}
	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