| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 133830 | MetB | Roller Coaster Railroad (IOI16_railroad) | 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 <algorithm>
#include <iostream>
#include <string.h>
#include <cstdlib>
#include <vector>
#include <string>
#include <bitset>
#include <math.h>
#include <queue>
#include <stack>
#include <set>
#include <map>
typedef long long ll;
typedef long double ld;
const ll MOD = 1e9 + 7, INF = 1e18 + 1;
using namespace std;
int p[1000000], sz[1000000];
set <int> mp;
struct stop
{
int x;
bool op, left;
bool operator < (const stop& b)
{
if (x == b.x) return op > b.op;
else return x < b.x;
}
};
struct edge
{
int u, v;
ll c;
bool operator < (const edge& b)
{
return c < b.c;
}
};
vector <stop> v;
int find (int x)
{
if (p[x] == x) return x;
else return p[x] = find (p[x]);
}
void unite (int a, int b)
{
a = find (a);
b = find (b);
if (a == b) return;
if (sz[a] < sz[b]) swap (a, b);
p[b] = a;
sz[a] += sz[b];
}
int ind (int a, vector <ll>& s)
{
return lower_bound (s.begin(), s.end(), a) - s.begin ();
}
ll plan_roller_coaster (vector <int> s, vector <int> t)
{
ll ans = 0, balance = 0;
vector <int> coord;
for (int i = 0; i < s.size (); i++)
{
if (s[i] > t[i])
{
v.push_back ({t[i], true, true});
v.push_back ({s[i], false, true});
}
else
{
v.push_back ({s[i], true, false});
v.push_back ({t[i], false, false});
}
mp.insert (s[i]);
mp.insert (t[i]);
}
for (auto a : mp)
coord.push_back (a);
for (int i = 0; i < coord.size (); i++)
{
sz[i] = 1;
p[i] = i;
}
v.push_back ({1, true, true});
v.push_back ({coord.back (), false, true});
for (int i = 0; i < s.size (); i++)
unite (ind (s[i], coord), ind (t[i], coord));
sort (v.begin(), v.end());
vector <edge> tr;
for (int i = 0; i < v.size (); i++)
{
if (v[i].left ^ v[i].op) balance++;
else balance--;
vector <edge> tr;
if (i != v.size () - 1)
{
ans += max (0LL, balance * ll (v[i+1].x - v[i].x));
if (balance) unite (ind (v[i].x, coord), ind (v[i+1].x, coord));
else tr.push_back ({ind (v[i].x, coord), ind (v[i+1].x, coord), (v[i+1].x - v[i].x)});
}
}
sort (tr.begin(), tr.end());
for (edge e : tr)
{
if (find (e.u) != find (e.v))
{
ans += e.c;
unite (e.u, e.v);
}
}
return ans;
}