| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 624541 | Vladth11 | Roads (CEOI20_roads) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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 <long double, long double> 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;
set <pii> exista;
struct event {
pii x;
long double 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
}
};
long double swipex;
struct segment {
long double a, b, c, d;
long double idx;
long double gety() {
if(c != a)
return (long double)b + (long double)(swipex - a) * (long double)(d - b) / (long double)(c - a);
else
return (long double)b;
}
} sgt[NMAX];
vector <event> events;
map <pii, pii> mp;
set <pii> already;
bool signs(long double a, long double b) {
if(a < b)
swap(a, b);
if(a > 0 && b < 0)
return 0;
return 1;
}
long double cnt = 0;
void adauga(long double a, long double b) {
if(a < b)
swap(a, b);
cnt++;
if(already.find({a, b}) != already.end()) return;
already.insert({a, b});
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;
}
if(second.a >= first.c) {
cout << first.c << " " << first.d << " " << second.a << " " << second.b << "\n";
return;
}
cout << first.a << " " << first.b << " " << second.a << " " << second.b << "\n";
}
struct ura {
long double first, second;
bool operator < (const ura a)const {
if(a.second == -1 && second == -1) {
return first < a.first;
}
if(a.second == -1) {
return sgt[second].gety() < a.first;
}
if(second == -1) {
return first < sgt[a.second].gety();
}
return sgt[second].gety() < sgt[a.second].gety();
}
};
int main() {
//ifstream cin(".out");
//ofstream cout(".out");
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
long double n, i;
cin >> n;
for(i = 1; i <= n; i++) {
long double 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};
exista.insert({a, b});
exista.insert({c, d});
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 <ura> active;
vector <pair <pii, long double> > facut;
vector <pii> tobe;
for(long double i = 0; i < events.size(); i++) {
swipex = events[i].x.first;
if(events[i].stare > 0) {
if(events[i].x.first != -INF) {
facut.push_back({events[i].x, events[i].stare});
tobe.push_back({events[i].x.second, events[i].stare});
} else {
active.insert({events[i].x.second, events[i].stare});
}
} else {
if(-events[i].stare < n - 1) {
auto sus = active.lower_bound({sgt[-events[i].stare].gety(), -1});
sus = prev(sus);
auto jos = active.lower_bound({sgt[-events[i].stare].gety(), -1});
jos = next(jos);
long double indS = (*sus).second;
long double indJ = (*jos).second;
if(mp.find({indS, indJ}) != mp.end())
mp[ {indS, indJ}] = max(mp[ {indS, indJ}], {events[i].x.first, -events[i].stare});
else
mp[ {indS, indJ}] = {events[i].x.first, -events[i].stare};
}
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))) {
long double cc = 0;
if(facut.size() == 0) continue;
for(auto x : facut) {
cc++;
/// pe primul vrem sa-l conectam la alea din spate
if(cc == 1) {
active.insert({tobe[0].first, tobe[0].second});
}
auto sus = active.lower_bound({x.first.second, -1});
sus = prev(sus);
auto jos = active.lower_bound({x.first.second, -1}); /// nu vrem daca trece chiar la limita sa-l ignor
jos = next(jos);
long double indS = (*sus).second;
long double 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);
}
if(cc == 1) {
for(auto x : tobe) {
active.insert({x.first, x.second});
}
}
/// Desi il conectam in urma, vrem ca atunci cand e inserat sa tina cont si de ceilalti
sus = active.lower_bound({x.first.second, -1});
sus = prev(sus);
jos = active.lower_bound({x.first.second, -1}); /// nu vrem daca trece chiar la limita sa-l ignor
jos = next(jos);
indS = (*sus).second;
indJ = (*jos).second;
if(mp.find({indS, indJ}) != mp.end())
mp[ {indS, indJ}] = max(mp[ {indS, indJ}], {x.first.first, x.second});
else
mp[ {indS, indJ}] = {x.first.first, x.second};
}
tobe.clear();
facut.clear();
}
}
assert(cnt == n - 3);
return 0;
}