Submission #787501

#	Time	Username	Problem	Language	Result	Execution time	Memory
787501		NothingXD	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	175 ms	20076 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef complex<double> point;

void debug_out(){cerr << endl;}

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T){
	cerr << H << ' ';
	debug_out(T...);
}

#define debug(...) cerr << "(" << #__VA_ARGS__ << "): ", debug_out(__VA_ARGS__)
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define MP(x, y) make_pair(x, y)

const int maxn = 5e5 + 10;

int n, val[maxn], par[maxn];
vector<int> num;

int getpar(int v){
	return (par[v] == -1? v: par[v] = getpar(par[v]));
}

bool merge(int u, int v){
	if ((u = getpar(u)) == (v = getpar(v))) return false;
	par[u] = v;
	return true;
}

long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
	memset(par, -1, sizeof par);
	n = s.size();
	ll k = 0;
	for (int i = 0; i < n; i++){
		num.push_back(s[i]);
		num.push_back(t[i]);
		k += t[i] - s[i];
	}
	k -= 1e9 + 7;
	num.push_back(0);
	num.push_back(1e9 + 7);
	sort(all(num));
	num.resize(distance(num.begin(), unique(all(num))));
	for (int i = 0; i < n; i++){
		int ids = lower_bound(all(num), s[i]) - num.begin();
		int idt = lower_bound(all(num), t[i]) - num.begin();
		merge(ids, idt);
		val[ids]++;
		val[idt]--;
	}
	n = num.size();
	ll ans = 0;
	int cnt = 0;
	vector<pair<int,pii>> edge;
	for (int i = 1; i < n; i++){
		if (cnt <= 0){
			ans += 1ll * (1-cnt) * (num[i] - num[i-1]);
			merge(i, i-1);
		}
		else if (cnt > 1){
			ans += 1ll * (cnt-1) * (num[i] - num[i-1]);
			merge(i, i-1);
		}
		cnt += val[i];
		edge.push_back({(num[i] - num[i-1]) * 2, {i-1, i}});
	}
	sort(all(edge));
	for (auto x: edge){
		if (merge(x.S.F, x.S.S)) ans += x.F;
	}


	ans = (ans - k) / 2 + k;

    return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 36 / 36