题解 | 栈和排序

#include <bits/stdc++.h>
using ll = long long ; 
using namespace std;
#define endl '\n'
#define pb push_back
#define ull unsigned long long
#define all(a) a.begin(), a.end()
#define vi vector<ll>
#define vii vector<vector<ll>>
#define fi first 
#define se second
#define vs vector<string>
#define eb emplace_back
#define in insert
#define pf push_front
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); i++)
const int inf = 2e18 + 9 ;
const int mod1 = 1e9 + 7 ; 
const int mod2 = 998244353 ; 
typedef pair<int, int> pll;
typedef long double db;

inline ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a;};
inline int read(){int x = 0;short f = 1;char c = getchar();while ((c < '0' || c > '9') && c != '-')c = getchar();if (c == '-')f = -1, c = getchar();while (c >= '0' && c <= '9')x = x * 10 + c - '0', c = getchar();x *= f;return x;}
inline ll qsm(ll a , ll b){ll res = 1 ; while(b){if(b & 1){res *= a ; }b >>= 1 ; a *= a ; }return res ; }
int dir[4][2] = {{1 , 0} , {-1 , 0} , {0 , 1} , {0 , -1}};
int dirx[8] = {-1, -1, -1, 0, 0, 1, 1, 1}; 
int diry[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
void work() 
{
    int n ; cin >> n ; 
    int j = 0 ; 
    vi a(n) ; 
    for(int i = 0 ; i < n ; i++)
    {
        cin >> a[i] ; 
    }
    vi b = a ; 
    sort(all(b) , greater()) ;
    stack<int>q ;
    vi ans ; 
    for(int i = 0 ; i < n ; i++)
    {
        if(a[i] == b[j])
        {
            ans.pb(a[i]) ; 
            j++ ; 
            while(q.top() == b[j])
            {
                ans.pb(q.top()) ; 
                q.pop() ;
                j++ ; 
            }
        }
        else 
        {
            q.push(a[i]) ;
        }
    } 
    if(j != n - 1)
    {
        while(q.size())
        {
            ans.pb(q.top()) ;
            q.pop() ; 
        }
    }
    for(int i : ans)
    {
        cout << i << " " ; 
    }
    return ;
}
signed main() 
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    while (t--) 
    {
        work();
    }
    return 0;
}