wind training

Code

#include             <bits/stdc++.h>
#define pb           push_back
#define fi           first
#define se           second
#define int          long long 
#define pii          pair<long long, long long>
#define endl         "\n"
#define TIME         (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i)      (1ll<<(i))
#define FILE(A)      freopen(A".INP", "r", stdin); freopen(A".OUT", "w", stdout)
#define BIT(Mask, i) (((Mask)>>(i))&1)

using namespace std;

const int N    = 1e5+5;
const int MOD  = 1e9+7;
const int INF  = 1e16 ;
const int Lim  = 1e9  ;
const int BASE = 31   ;

int n, a[N];

void solve() {
    for (int i=1;i <= n;i++) {
        cin >> a[i];
    }
    stack<int> s;
    int cur = 1;
    for (int i=1;i <= n+1;i++) {
        while(!s.empty() && cur == s.top()) {
            cur++;
            s.pop();
        }
        if (cur == a[i]) {
            cur++;
        }
        else {
            s.push(a[i]);
        }
    }
    if (cur == n+1) {
        cout << "yes";
    }
    else {
        cout << "no";
    }
}

signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    
    while(cin >> n) {
        if (!n) break;
        solve();
        cout << endl;
    }
    
    cerr << "Time elapsed: " << TIME << "s.\n";
    return 0;
}

// Nguyen Minh Hieu - 2008 - Gia Lai.
// https://hieuhfgr.pythonanywhere.com/
// .-.. --- ...- . .-.. -.--