Submission #794278

#	Time	Username	Problem	Language	Result	Execution time	Memory
794278		becaido	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	178 ms	18756 KiB

railroad

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifndef WAIMAI
#include "railroad.h"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout (T t, U...u) {cout << t << (sizeof... (u) ? ", " : ""), dout (u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

const int INF = 1e9;
const int SIZE = 4e5 + 5;

int n, m;
ll ans;
int d[SIZE];
vector<int> lis;
int to[SIZE], h[SIZE];

int dsu(int x) {
    return x == to[x] ? x : (to[x] = dsu(to[x]));
}
bool mer(int a, int b) {
    a = dsu(a), b = dsu(b);
    if (a == b) return 0;
    if (h[a] < h[b]) swap(a, b);
    to[b] = a;
    h[a] += (h[a] == h[b]);
    return 1;
}

ll plan_roller_coaster(vector<int> s, vector<int> t) {
    n = s.size();
    lis.clear();
    lis.pb(1), lis.pb(INF);
    lis.insert(lis.end(), s.begin(), s.end());
    lis.insert(lis.end(), t.begin(), t.end());
    sort(lis.begin(), lis.end());
    lis.erase(unique(lis.begin(), lis.end()), lis.end());
    m = lis.size();
    iota(to, to + m, 0);
    fill(h, h + m, 0);
    fill(d, d + m, 0);
    ans = 0;
    mer(0, m - 1);
    d[m - 1]++, d[0]--;
    FOR (i, 0, n - 1) {
        int l = lower_bound(lis.begin(), lis.end(), s[i]) - lis.begin();
        int r = lower_bound(lis.begin(), lis.end(), t[i]) - lis.begin();
        d[l]++, d[r]--;
        mer(l, r);
    }
    vector<pair<int, int>> e;
    FOR (i, 0, m - 2) {
        if (d[i] != 0) {
            mer(i, i + 1);
            if (d[i] > 0) ans += 1ll * d[i] * (lis[i + 1] - lis[i]);
        }
        e.pb(lis[i + 1] - lis[i], i);
        d[i + 1] += d[i];
    }
    sort(e.begin(), e.end());
    for (auto [w, i] : e) if (mer(i, i + 1)) ans += w;
    return ans;
}

/*
in1
4
1 7
4 3
5 8
6 6
out1
3
*/

#ifdef WAIMAI
int main() {
    int n;
    assert(1 == scanf("%d", &n));
    vector<int> s(n), t(n);
    for (int i = 0; i < n; ++i)
        assert(2 == scanf("%d%d", &s[i], &t[i]));
    long long ans = plan_roller_coaster(s, t);
    printf("%lld\n", ans);
    return 0;
}
#endif

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