| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1082485 | 2024-08-31T13:18:48 Z | Boas | Longest Trip (IOI23_longesttrip) | C++17 | 0 ms | 0 KB |
#include "longesttrip.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <typename T1, typename T2>
using indexed_map = tree<T1, T2, less<T1>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using indexed_set = indexed_map<T, null_type>;
#define loop(x, i) for (int i = 0; i < (x); i++)
#define loop1(x, i) for (int i = 1; i <= (x); i++)
#define rev(x, i) for (int i = (int)(x) - 1; i >= 0; i--)
#define itloop(x) for (auto it = begin(x); x != end(x); it++)
#define itrev(x) for (auto it = rbegin(x); x != rend(x); it++)
#define INF32 ((int32_t)(2e9 + 1))
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define removeIn(x, l) l.erase(find(ALL(l), x))
#define pb push_back
#define sz(x) (int)(x).size()
#define F first
#define S second
#define var const auto &
#define foreach(l) for (var e : l)
typedef int8_t i8;
typedef int16_t i16;
typedef int32_t i32;
typedef int64_t i64;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<i32> vi32;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vi32> vvi32;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<vii> vvii;
typedef vector<viii> vviii;
typedef set<int> si;
typedef set<ii> sii;
typedef set<iii> siii;
typedef vector<si> vsi;
typedef vector<sii> vsii;
typedef vector<vsi> vvsi;
typedef vector<string> vstr;
typedef vector<vector<string>> vvstr;
typedef vector<bool> vb;
typedef vector<vb> vvb;
vi longest_trip(int N, int D)
{
if (D >= 2)
{
vi res(N);
iota(ALL(res), 0);
if (D == 3)
{
return res;
}
si resterend;
loop1(N - 1, i) resterend.insert(res[i]);
loop1(N - 1, i)
{
auto it = resterend.begin();
if (are_connected({res[i - 1]}, {*it}))
{
res[i] = *it;
resterend.erase(it);
}
else
{
if (resterend.size() == 1)
{
res.insert(res.begin(), *it);
res.pop_back();
return res;
}
res[i] = *next(it);
resterend.erase(next(it));
}
}
return res;
}
else
{
map<ii, bool> con;
auto getCon = [&](int a, int b) -> bool
{
if (a>b) swap(a,b);
assert(a!=b);
if (con.count({a, b})) return con[{a, b}];
return con[{a, b}] = are_connected({a}, {b});
};
deque<int> path1, path2;
path1.pb(0);
for (int i = 1; i < N; i++)
{
if (getCon(i, path1.back()))
{
path1.pb(i);
}
else if (getCon(i, path2[0]))
{
path2.push_front(i);
}
else
{
for (int v:path2) path1.pb(v);
path2.clear();
path2.pb(i);
}
}
vi uq, vq, res;
for (int i : path1)
for (int j : path2)
{
uq.pb(i);
vq.pb(j);
}
if (sz(path1) < sz(path2)) swap(path1, path2);
if (are_connected(uq, vq))
{
if (!getCon(path1[0], path1.back()))
{
if (getCon(path1[0], path2[0]))
{
rev(sz(path1), ix) res.pb(path1[ix]);
for (int i : path2) res.pb(i);
return res;
}
else
{
for (int i : path1) res.pb(i);
for (int i : path2) res.pb(i);
return res;
}
}
int lo = 0, hi = sz(uq)-1;
while (hi >lo)
{
int mid = (lo+hi)/2;
vi uq2(begin(uq), begin(uq)+mid+1);
vi vq2(begin(vq), begin(vq)+mid+1);
if (are_connected(uq2, vq2))
{
hi = mid;
}
else lo = mid +1;
}
int s1 = uq[lo], s2 = vq[lo];
loop(sz(path1), ix)
{
if (path1[ix] == uq[lo])
{
s1 = ix;
}
}
loop(sz(path2), ix)
{
if (path2[ix] == vq[lo])
{
s2 = ix;
}
}
for (int i = s1 + 1; i < sz(path1); i++)
{
res.pb(path1[i]);
}
for (int i = 0; i <= s1; i++)
{
res.pb(path1[i]);
}
for (int i = s2; i < sz(path2); i++)
{
res.pb(path2[i]);
}
for (int i = 0; i < s2; i++)
{
res.pb(path2[i]);
}
}
else
{
if (sz(path1)>sz(path2))
{
for (int v : path1)
res.pb(v);
}
else
{
for (int v : path2)
res.pb(v);
}
return res;
}
assert(sz(res) == N);
loop(sz(res) - 1, i) assert(con[res[i]][res[i + 1]]);
return res;
}
throw;
return {};
}