verify/yosupo/data-structure/cartesian-tree/cartesian_tree.test.cpp
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Code
#define PROBLEM "https://judge.yosupo.jp/problem/cartesian_tree"
#include "template.hpp"
#include "data-structure/cartesian-tree.hpp"
int main(){
cin.tie(nullptr)->sync_with_stdio(false);
int n;
cin >> n;
vector<int> a(n);
for(auto &x:a)cin >> x;
CartesianTree<int,true> ct(a);
auto ans=ct.par;
ans[ct.root]=ct.root;
for(auto x:ans)cout << x << " ";
}
#line 1 "verify/yosupo/data-structure/cartesian-tree/cartesian_tree.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/cartesian_tree"
#line 2 "template.hpp"
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using db = long double;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
template<class T>
using PQ = priority_queue<T,vector<T>,greater<T>>;
const int INF=INT_MAX/2;
const ll LINF=LLONG_MAX/4;
const db DINF=numeric_limits<db>::infinity();
const db EPS=1e-9;
const db PI=acos(db(-1));
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define SZ(a) (int)(a.size())
#define SORT(a) sort(ALL(a))
#define RSORT(a) sort(RALL(a))
#define REV(a) reverse(ALL(a))
#define UNI(a) a.erase(unique(ALL(a)),a.end())
#define LB(a,x) (int)(lower_bound(ALL(a),x)-a.begin())
#define UB(a,x) (int)(upper_bound(ALL(a),x)-a.begin())
#define FIND(a,x) (int)(find(ALL(a),x)-a.begin())
#define COUNT(a,x) (int)count(ALL(a),x)
#define MIN(a) *min_element(ALL(a))
#define MAX(a) *max_element(ALL(a))
template<class T,class U>
bool chmin(T &a,U b){return b<a?a=b,1:0;}
template<class T,class U>
bool chmax(T &a,U b){return a<b?a=b,1:0;}
template<class T>
T floor(T a,T b){return a/b-((a^b)<0&&a%b);}
template<class T>
T ceil(T a,T b){return a/b+((a^b)>=0&&a%b);}
int popcnt(ll x){return __builtin_popcountll(x);}
int topbit(ll x){return x==0?-1:63-__builtin_clzll(x);}
int lowbit(ll x){return x==0?-1:__builtin_ctzll(x);}
template<class T,class U>
T SUM(const U &a){return accumulate(ALL(a),T{});}
template<class T>
vector<int> argsort(const vector<T> &a){
vector<int> p(SZ(a));
iota(ALL(p),0);
stable_sort(ALL(p),[&](int i,int j){return a[i]<a[j];});
return p;
}
template<class T,size_t D=0>
struct VecBuilder{
array<size_t,D> d;
VecBuilder<T,D+1> operator[](size_t n)const{
VecBuilder<T,D+1> res{};
for(size_t i=0;i<D;i++)res.d[i]=d[i];
res.d[D]=n;
return res;
}
template<size_t I=0>
auto build(const T &x)const{
if constexpr(I+1==D)return vector<T>(d[I],x);
else return vector<decltype(build<I+1>(x))>(d[I],build<I+1>(x));
}
auto operator()(const T &x=T())const{
static_assert(D>0);
return build(x);
}
};
template<class T>
inline constexpr VecBuilder<T> VEC{};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
#line 3 "data-structure/cartesian-tree.hpp"
/**
* Author: Teetat T.
* Date: 2025-10-12
* Description: Cartesian Tree.
*/
template<class T,bool IS_MIN>
struct CartesianTree{
int n;
vector<T> &a;
vector<pair<int,int>> range;
vector<int> lch,rch,par;
int root;
CartesianTree(vector<T> &_a):n((int)_a.size()),a(_a){
range.assign(n,{-1,-1});
lch=rch=par=vector<int>(n,-1);
auto cmp=[&](int i,int j)->bool {
if(IS_MIN)return a[i]<a[j]||(a[i]==a[j]&&i<j);
return a[i]>a[j]||(a[i]==a[j]&&i<j);
};
vector<int> st;
for(int i=0;i<n;i++){
while(!st.empty()&&cmp(i,st.back())){
lch[i]=st.back();
st.pop_back();
}
range[i].first=(st.empty()?-1:st.back())+1;
st.emplace_back(i);
}
st.clear();
for(int i=n-1;i>=0;i--){
while(!st.empty()&&cmp(i,st.back())){
rch[i]=st.back();
st.pop_back();
}
range[i].second=(st.empty()?n:st.back())-1;
st.emplace_back(i);
}
for(int i=0;i<n;i++)if(lch[i]!=-1)par[lch[i]]=i;
for(int i=0;i<n;i++)if(rch[i]!=-1)par[rch[i]]=i;
for(int i=0;i<n;i++)if(par[i]==-1)root=i;
}
};
#line 4 "verify/yosupo/data-structure/cartesian-tree/cartesian_tree.test.cpp"
int main(){
cin.tie(nullptr)->sync_with_stdio(false);
int n;
cin >> n;
vector<int> a(n);
for(auto &x:a)cin >> x;
CartesianTree<int,true> ct(a);
auto ans=ct.par;
ans[ct.root]=ct.root;
for(auto x:ans)cout << x << " ";
}
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