Submission #600615

#	Time	Username	Problem	Language	Result	Execution time	Memory
600615		wiwiho	Roller Coaster Railroad (IOI16_railroad)	C++14	100 / 100	189 ms	35520 KiB

railroad

#include "railroad.h"

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 2147483647;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

ll ifloor(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a < 0) return (a - b + 1) / b;
    else return a / b;
}

ll iceil(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a > 0) return (a + b - 1) / b;
    else return a / b;
}

vector<int> dsu;

int findDSU(int a){
    if(dsu[a] != a) dsu[a] = findDSU(dsu[a]);
    return dsu[a];
}

void unionDSU(int a, int b){
    a = findDSU(a); b = findDSU(b);
    dsu[b] = a;
}

struct info{
    int x, id, ty;
};

struct seg{
    int id, l, r;
};

long long plan_roller_coaster(vector<int> S, vector<int> T){
    int n = (int) S.size();

    vector<info> v;
    for(int i = 0; i < n; i++){
        //cerr << "test " << i << " : " << S[i] << " " << T[i] << "\n";
        v.eb(info({S[i], i, 1}));
        v.eb(info({T[i], i, 0}));
    }
    v.eb(info({0, n, 0}));
    v.eb(info({1000000001, n, 1}));

    sort(iter(v), [&](info x, info y){ return mp(x.x, x.ty) < mp(y.x, y.ty); });
    vector<info> nv;
    int ts = n + 1;

    ll ans = 0;

    deque<info> lone;
    int cnt = 0;
    for(info& i : v){
        int x = i.x, id = i.id, ty = i.ty;
        if(ty == 1){
            if(cnt) cnt--;
            else lone.eb(i);
            continue;
        }
        if(lone.empty()){
            cnt++;
            continue;
        }
        nv.eb(info({lone.front().x, ts++, 0}));
        nv.eb(info({x, ts++, 1}));
        ans += x - lone.front().x;
        i.x = lone.front().x;
        lone.pof;
    }

    for(info i : nv) v.eb(i);
    sort(iter(v), [&](info x, info y){ return mp(x.x, x.ty) < mp(y.x, y.ty); });

    dsu.resize(v.size());
    iota(iter(dsu), 0);
    

    vector<int> left;
    vector<seg> b;
    
    for(info i : v){
        int x = i.x, id = i.id, ty = i.ty;
        if(ty == 0){
            left.eb(id);
            b.eb(seg({id, x, -1}));
            continue;
        }
        int l = left.back();
        left.pob;
        unionDSU(l, id);
        while(b.back().id != l){
            unionDSU(b.back().id, id);
            b.pob;
        }
        b.back().r = x;
    }

    vector<pair<int, pii>> e;
    for(int i = 0; i + 1 < (int)b.size(); i++){
        if(findDSU(b[i].id) == findDSU(b[i + 1].id)) continue;
        e.eb(mp(b[i + 1].l - b[i].r, mp(b[i].id, b[i + 1].id)));
    }
    lsort(e);
    for(auto i : e){
        int w = i.F, u = i.S.F, v = i.S.S;
        if(findDSU(u) == findDSU(v)) continue;
        ans += w;
        unionDSU(u, v);
    }
    
    return ans;
}

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:106:22: warning: unused variable 'id' [-Wunused-variable]
  106 |         int x = i.x, id = i.id, ty = i.ty;
      |                      ^~

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