verify/yosupo/tree/cartesian_tree.test.cpp

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• Last update: 2026-04-15 22:12:04+07:00
• Problem: https://judge.yosupo.jp/problem/cartesian_tree

Depends on

• data-structure/cartesian-tree.hpp
• template.hpp

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/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;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#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 SZ(a) (int)(a.size())
#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 MIN(a) *min_element(ALL(a))
#define MAX(a) *max_element(ALL(a))

using ll = long long;
using db = long double;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;

const int INF=INT_MAX/2;
const ll LINF=LLONG_MAX/4;
const db DINF=numeric_limits<db>::infinity();
const int MOD=998244353;
const int MOD2=1000000007;
const db EPS=1e-9;
const db PI=acos(db(-1));

template<class T>
using PQ = priority_queue<T,vector<T>,greater<T>>;

#define vv(T,a,n,...) vector<vector<T>> a(n,vector<T>(__VA_ARGS__))
#define vvv(T,a,n,m,...) vector<vector<vector<T>>> a(n,vector<vector<T>>(m,vector<T>(__VA_ARGS__)))
#define vvvv(T,a,n,m,k,...) vector<vector<vector<vector<T>>>> a(n,vector<vector<vector<T>>>(m,vector<vector<T>>(k,vector<T>(__VA_ARGS__))))

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,class U>
T SUM(const U &a){return accumulate(ALL(a),T{});}

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/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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