Submission #764480

#	Time	Username	Problem	Language	Result	Execution time	Memory
764480		marvinthang	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	158 ms	15080 KiB

railroad

/*************************************
*    author: marvinthang             *
*    created: 23.06.2023 19:16:39    *
*************************************/

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

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

struct DisjointSet {
    
    int n, *lab = nullptr;

    DisjointSet(int _n = 0) {
        resize(_n);
    }

    void reset(void) {
        memset(lab, -1, (n + 1) * sizeof(int));
    }

    void resize(int _n) {
         if (lab != nullptr) delete[] lab;
         n = _n;
         lab = new int[n + 1];
         reset();
    }

    int find(int u) {
        assert(u <= n);
        return lab[u] < 0 ? u : lab[u] = find(lab[u]);
    }

    bool connected(int u, int v) { return find(u) == find(v); }
    bool isRoot(int u) { return lab[u] < 0; }
    int size(int u) { return -lab[find(u)]; }

    bool join(int u, int v) {
        if ((u = find(u)) == (v = find(v))) return false;
        if (lab[u] > lab[v]) swap(u, v);
        lab[u] += lab[v];
        lab[v] = u;
        return true;
    }

};

using DSU = DisjointSet;

// end of template

long long plan_roller_coaster(vector <int> s, vector <int> t) {
    int n = (int) s.size();
    vector <int> v(s);
    v.insert(v.end(), ALL(t));
    sort(ALL(v));
    v.erase(unique(ALL(v)), v.end());
    int m = v.size();
    vector <int> pref(m);
    pref[0] = -1;
    DSU dsu(m);
    REP(i, n) {
        s[i] = lower_bound(ALL(v), s[i]) - v.begin();
        t[i] = lower_bound(ALL(v), t[i]) - v.begin();
        ++pref[s[i]];
        --pref[t[i]];
        dsu.join(s[i], t[i]);
    }
    long long res = 0;
    vector <pair <int, int>> edges;
    REP(i, m - 1) {
        pref[i + 1] += pref[i];
        if (pref[i] > 0) res += 1LL * pref[i] * (v[i + 1] - v[i]);
        if (pref[i]) dsu.join(i, i + 1);
        else edges.emplace_back(v[i + 1] - v[i], i);
    }
    sort(ALL(edges));
    for (auto [w, u]: edges) if (dsu.join(u, u + 1)) res += w;
    return res;
}

#ifdef LOCAL
#include "railroad.h"
#include <cstdio>
#include <cassert>

int main() {
    file("railroad");
    int n;
    assert(1 == scanf("%d", &n));
    std::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