Submission #1036992

#	Time	Username	Problem	Language	Result	Execution time	Memory
1036992		AmirAli_H1	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	111 ms	17484 KiB

railroad

// In the name of Allah
 
#include <bits/stdc++.h>
#include "railroad.h"
using namespace std;
 
typedef		long long int			ll;
typedef		long double				ld;
typedef		pair<int, int>			pii;
typedef		pair<ll, ll>			pll;
typedef		complex<ld>				cld;
 
#define		all(x)					(x).begin(),(x).end()
#define		len(x)					((ll) (x).size())
#define		F						first
#define		S						second
#define		pb						push_back
#define		sep						' '
#define		endl					'\n'
#define		Mp						make_pair
#define		kill(x)					cout << x << '\n', exit(0)
#define		set_dec(x)				cout << fixed << setprecision(x);
#define		file_io(x,y)			freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int maxn = 2e5 + 4;
const ll oo = 1e18 + 4;

int n;
pll A1[maxn], A2[maxn];
int p[maxn], sz[maxn], num;
vector<pair<ll, pii>> E;

int get(int a) {
	return (p[a] == a) ? a : p[a] = get(p[a]);
}

void merge(int a, int b) {
	a = get(a); b = get(b);
	if (a == b) return ;
	if (sz[a] > sz[b]) swap(a, b);
	p[a] = b; sz[b] += sz[a]; sz[a] = 0; num--;
}

ll plan_roller_coaster(vector<int> s, vector<int> t) {
	n = len(s);
	for (int i = 0; i < n; i++) {
		A1[i] = Mp(s[i], i); A2[i] = Mp(t[i], i);
	}
	A1[n] = Mp(oo, n); A2[n] = Mp(-oo, n); n++;
	
	sort(A1, A1 + n); sort(A2, A2 + n);
	iota(p, p + n, 0); fill(sz, sz + n, 1); num = n;
	
	ll ans = 0;
	for (int i = 0; i < n; i++) {
		merge(A1[i].S, A2[i].S);
		ans += max(0ll, A2[i].F - A1[i].F);
		if (i + 1 < n) {
			ll w = max(0ll, A2[i + 1].F - A1[i].F) + max(0ll, A2[i].F - A1[i + 1].F);
			w -= max(0ll, A2[i].F - A1[i].F) + max(0ll, A2[i + 1].F - A1[i + 1].F);
			E.pb(Mp(w, Mp(A1[i].S, A2[i + 1].S)));
		}
	}
	sort(all(E));
	
	for (auto f : E) {
		if (num == 1) break;
		int u = f.S.F, v = f.S.S; ll w = f.F;
		if (get(u) != get(v)) {
			merge(u, v); ans += w;
		}
	}
	
	return ans;
}

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