CSES-solutions/CSES Problem Set/Planets Cycles.cpp
Segcolt 8b03716512 Add a lot more of my solutions.
I don't remember which ones doesn't pass though
2025-09-12 14:51:10 -03:00

167 lines
3.2 KiB
C++

/* Problem URL: https://cses.fi/problemset/task/1751 */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vi next(n);
repv(i, next) {
cin >> i;
i--;
}
V<bool> vis(n);
V<bool> frame(n);
V<bool> cycle(n);
vi cyclesize(n);
auto getcycle = [&](int i) {
set<int> rem;
frame[i] = true;
vis[i] = true;
rem.insert(i);
int j = next[i];
while (!vis[j] && !frame[j]) {
vis[j] = true;
frame[j] = true;
rem.insert(j);
j = next[j];
}
if (!frame[j]) {
repv(i, rem) {
frame[i] = false;
}
return;
}
int now = 1;
i = j;
j = next[j];
cycle[i] = true;
while (j != i) {
cycle[j] = true;
now++;
j = next[j];
}
cyclesize[i] = now;
j = next[j];
while (j != i) {
cyclesize[j] = now;
j = next[j];
}
repv(i, rem) {
frame[i] = false;
}
};
rep(i, n) {
getcycle(i);
}
vi memo(n, -1);
rep(i, n) {
if (cycle[i]) {
memo[i] = cyclesize[i];
}
}
function<int(int)> dfs = [&](int i) {
int &ans = memo[i];
if (ans != -1) {
return ans;
}
ans = dfs(next[i]) + 1;
return ans;
};
rep(i, n) {
cout << dfs(i) << ' ';
}
cout << '\n';
}