514 - Rails

#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define endl '\n'
#define sz(x) int(x.size())
#define all(x) x.begin(), x.end()

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int n;
    while (cin >> n, n) {
        vector<int> nums(n);
        while (cin >> nums[0], nums[0]) {
            for (int i = 1; i < n; i++) cin >> nums[i];
            stack<int> stk, station;
            for (int i = n; i >= 1; i--) stk.push(i);
            int idx = 0;
            bool done = true;
            while (done) {
                done = false;
                while (sz(station) && station.top() == nums[idx]) {
                    idx++;
                    done = true;
                    station.pop();
                }
                while (sz(stk) && stk.top() != nums[idx]) station.push(stk.top()), stk.pop();
                if (sz(stk)) {
                    done = true;
                    idx++;
                    stk.pop();
                }
            }
            cout << (idx == n ? "Yes" : "No") << endl;
        }
        cout << endl;
    }
}