Submission #624453

#	Time	Username	Problem	Language	Result	Execution time	Memory
624453		Vladth11	Roads (CEOI20_roads)	C++14	0 / 100	71 ms	6616 KiB

roads

#include <bits/stdc++.h>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "

using namespace std;
typedef long long ll;
typedef pair <int, int> pii;

const ll NMAX = 100001;
const ll VMAX = 101;
const ll INF = 1e9;
const ll MOD = 1000000007;
const ll BLOCK = 447;
const ll base = 117;
const ll nr_of_bits = 18;
const ll inv2 = 500000004;

struct event {
    pii x;
    int stare;
    bool operator < (const event a) {
        if(a.x.first != x.first) {
            return x.first < a.x.first;
        }
        if(a.stare != stare) {
            return stare > a.stare;
        }
        return x.second > a.x.second; /// Nu ar trb sa aiba importanta, dar e necesar sa nu busesc sortarea
    }
};

struct segment {
    int a, b, c, d;
    int idx;
} sgt[NMAX];

vector <event> events;
map <pii, pii> mp;

bool signs(int a, int b){
    if(a < b)
        swap(a, b);
    if(a > 0 && b < 0)
        return 0;
    return 1;
}

int cnt = 0;

void adauga(int a, int b){
    cnt++;
    segment first = sgt[a];
    segment second = sgt[b];
    if(first.b < second.b){
        swap(first, second);
    }else if(first.b == second.b){
        if(first.a < second.a){
            swap(first, second);
        }
    }
    if(first.a >= second.c){
        cout << first.a << " " << first.b << " " << second.c << " " << second.d << "\n";
        return;
    }
    cout << first.a << " " << first.b << " " << second.a << " " << second.b << "\n";
}

int main() {
    //ifstream cin(".in");
    //ofstream cout(".out");
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, i;
    cin >> n;
    for(i = 1; i <= n; i++) {
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        if(a > c) {
            swap(b, d);
            swap(a, c);
        } else if(a == c) {
            if(b > d)
                swap(b, d); /// nu stiu daca e nevoie
        }
        sgt[i] = {a, b, c, d, i};
        events.push_back({{a, b}, i});
        events.push_back({{c, d}, -i});
    }
    n += 2;
    sgt[n - 1] = {-INF, -INF, INF, -INF, n - 1};
    events.push_back({{-INF, -INF}, n - 1});
    events.push_back({{INF, -INF}, -(n - 1)});
    sgt[n] = {-INF, INF, INF, INF, n};
    events.push_back({{-INF, INF}, n});
    events.push_back({{INF, INF}, -n});
    sort(events.begin(), events.end());
    set <pii> active;
    vector <pair <pii, int> > facut;
    for(int i = 0; i < events.size(); i++) {
        if(events[i].stare > 0){
            active.insert({events[i].x.second, events[i].stare});
            if(events[i].x.first != -INF)
                facut.push_back({events[i].x, events[i].stare});
        }else{
            active.erase({events[i].x.second, -events[i].stare});
        }
        if(i == events.size() || (events[i + 1].x.first != events[i].x.first || !signs(events[i + 1].stare, events[i].stare))){
            for(auto x : facut){
                auto sus = active.upper_bound({x.first.second, -1});
                sus = prev(sus);
                auto jos = active.lower_bound({x.first.second + 1, -1});
                int indS = (*sus).second;
                int indJ = (*jos).second;
                if(mp.find({indS, indJ}) == mp.end()){
                    if(sgt[indS].a != -INF){
                        adauga(indS, x.second);
                    }else if(sgt[indJ].a != -INF){
                        adauga(indJ, x.second);
                    }
                }else{
                    pii conectare = mp[{indS, indJ}];
                    adauga(conectare.second, x.second);
                }
                mp[{indS, indJ}] = max(mp[{indS, indJ}], {x.first.first, x.second});
            }
            facut.clear();
        }
    }
    assert(cnt == n - 3);
    return 0;
}

Compilation message (stderr)

roads.cpp: In function 'int main()':
roads.cpp:100:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<event>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  100 |     for(int i = 0; i < events.size(); i++) {
      |                    ~~^~~~~~~~~~~~~~~
roads.cpp:108:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<event>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |         if(i == events.size() || (events[i + 1].x.first != events[i].x.first || !signs(events[i + 1].stare, events[i].stare))){
      |            ~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 0 / 15
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 40