Aaaand... Another problem.

I didn't do this one earlier this year because I thought it was harder
than this, seriously, the statement was really confusing for me...

Data Structures and Libraries/Rails.cpp

@@ -0,0 +1,116 @@
+/* Problem URL: https://judge.beecrowd.com/en/problems/view/1062 */
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (size_t i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (size_t i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n;
+    while (cin >> n, n != 0) {
+        int num;
+        while (cin >> num, num != 0) {
+            vi ans(n);
+            ans[0] = num;
+            nrep(i, 1, n) {
+                cin >> ans[i];
+            }
+
+            stack<int> tmp;
+            size_t now = 0;
+            for (int i = 1; i <= n; i++) {
+                if (i == ans[now]) {
+                    now++;
+                    continue;
+                }
+
+                while (!tmp.empty() && tmp.top() == ans[now]) {
+                    tmp.pop();
+                    now++;
+                }
+
+                if (i != ans[now]) {
+                    tmp.push(i);
+                    continue;
+                }
+                now++;
+            }
+
+            while (!tmp.empty() && tmp.top() == ans[now]) {
+                tmp.pop();
+                now++;
+            }
+
+            cout << (tmp.empty() ? "Yes\n" : "No\n");
+        }
+        cout << '\n';
+    }
+}