And... Another problem.

This was so much simpler than anything I fucking thought about, what the
hell dude...

Data Structures and Libraries/Alien Ribonucleic Acid.cpp

@@ -0,0 +1,100 @@
+/* Problem URL: https://judge.beecrowd.com/en/problems/view/1242 */
+
+#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);
+
+    array<char, 256> map;
+    map['S'] = 'B';
+    map['B'] = 'S';
+    map['C'] = 'F';
+    map['F'] = 'C';
+
+    string s;
+
+    while (cin >> s) {
+        int ans = 0;
+        stack<char> st;
+
+        for (auto i : s) {
+            if (!st.empty() && st.top() == map[i]) {
+                st.pop();
+                ans++;
+            } else {
+                st.push(i);
+            }
+        }
+
+        cout << ans << '\n';
+    }
+}

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';
+    }
+}

Paradigms/Elegant Permuted Sum.cpp

@@ -0,0 +1,177 @@
+/* Problem URL: https://judge.beecrowd.com/en/problems/view/1055 */
+
+#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;
+}
+
+void push_min_back(list<int> &ans, map<int, int> &nums)
+{
+    auto itr = nums.begin();
+    ans.push_back(itr->first);
+    itr->second--;
+    if (itr->second == 0) {
+        nums.erase(itr);
+    }
+}
+
+void push_max_back(list<int> &ans, map<int, int> &nums)
+{
+    auto itr = prev(nums.end());
+    ans.push_back(itr->first);
+    itr->second--;
+    if (itr->second == 0) {
+        nums.erase(itr);
+    }
+}
+
+void push_min_front(list<int> &ans, map<int, int> &nums)
+{
+    auto itr = nums.begin();
+    ans.push_front(itr->first);
+    itr->second--;
+    if (itr->second == 0) {
+        nums.erase(itr);
+    }
+}
+
+void push_max_front(list<int> &ans, map<int, int> &nums)
+{
+    auto itr = prev(nums.end());
+    ans.push_front(itr->first);
+    itr->second--;
+    if (itr->second == 0) {
+        nums.erase(itr);
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int t;
+    cin >> t;
+    size_t i = 1;
+    while (t--) {
+        int n;
+        cin >> n;
+
+        list<int> ans;
+        map<int, int> nums;
+
+        while (n--) {
+            int num;
+            cin >> num;
+            nums[num]++;
+        }
+
+        map<int, int> tmp = nums;
+
+        push_max_back(ans, nums);
+
+        void (*push_to_list[])(list<int>&, map<int, int>&) {
+            push_min_back,
+            push_min_front,
+            push_max_back,
+            push_max_front
+        };
+
+        for (size_t i = 0; !nums.empty(); i = (i + 1) % 4) {
+            push_to_list[i](ans, nums);
+        }
+
+        ll sum = 0;
+        auto prev = ans.begin();
+        auto itr = next(prev);
+        while (itr != ans.end()) {
+            sum += abs(*prev - *itr);
+            prev++;
+            itr++;
+        }
+
+        swap(tmp, nums);
+
+        ans.clear();
+        push_min_back(ans, nums);
+
+        for (size_t i = 2; !nums.empty(); i = (i + 1) % 4) {
+            push_to_list[i](ans, nums);
+        }
+
+        ll tmp_sum = 0;
+        prev = ans.begin();
+        itr = next(prev);
+        while (itr != ans.end()) {
+            tmp_sum += abs(*prev - *itr);
+            prev++;
+            itr++;
+        }
+
+        cout << "Case " << i++ << ": " << max(sum, tmp_sum) << '\n';
+    }
+}