From 7454bd4d0d9b49fadf7bf96fac2d0f0ef750104c Mon Sep 17 00:00:00 2001
From: Segcolt <allanncintra@gmail.com>
Date: Mon, 16 Mar 2026 20:18:56 -0300
Subject: [PATCH] More problems

---
 .gitignore                               |   2 +
 CSES Problem Set/Convex Hull.cpp         | 192 +++++++++++++++++++++++
 CSES Problem Set/Point Location Test.cpp | 126 +++++++++++++++
 CSES Problem Set/Polygon Area.cpp        | 122 ++++++++++++++
 4 files changed, 442 insertions(+)
 create mode 100644 CSES Problem Set/Convex Hull.cpp
 create mode 100644 CSES Problem Set/Point Location Test.cpp
 create mode 100644 CSES Problem Set/Polygon Area.cpp

diff --git a/.gitignore b/.gitignore
index cd791a9..ee274c2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,3 +37,5 @@
 
 # Ignore gdb
 .gdb_history
+
+*sync*
diff --git a/CSES Problem Set/Convex Hull.cpp b/CSES Problem Set/Convex Hull.cpp
new file mode 100644
index 0000000..60d103d
--- /dev/null
+++ b/CSES Problem Set/Convex Hull.cpp	
@@ -0,0 +1,192 @@
+/* Problem URL: https://cses.fi/problemset/task/2195 */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int 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;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+struct pt {
+    ll x, y;
+    
+    pt() = default;
+    pt(ll x, ll y): x(x), y(y) {}
+    pt(const pt &a): x(a.x), y(a.y) {}
+
+    friend istream &operator >> (istream &is, pt &a) {
+        is >> a.x >> a.y;
+        return is;
+    }
+
+    friend ostream &operator << (ostream &os, pt a) {
+        os << a.x << ' ' << a.y << '\n';
+        return os;
+    }
+
+    ll operator ^ (pt b) {
+        return x * b.y - y * b.x;
+    }
+
+    pt operator - (pt b) {
+        return pt(x - b.x, y - b.y);
+    }
+
+    bool operator < (pt b) {
+        if (x == b.x) {
+            return y < b.y;
+        }
+        return x < b.x;
+    }
+};
+
+ll sarea2(pt a, pt b, pt c) {
+    return (b - a) ^ (c - b);
+}
+
+int ccw(pt a, pt b, pt c)
+{
+    ll ar = sarea2(a, b, c);
+    return (ar > 0) - (ar < 0);
+}
+
+V<pt> convex_hull(V<pt> v)
+{
+    sortv(v);
+    if (v.size() <= 2) {
+        return v;
+    }
+
+    int n = v.size();
+
+    V<pt> ac;
+    V<pt> tmp;
+
+    rep(i, n) {
+        while (ac.size() >= 2 && ccw(ac.end()[-2], ac.end()[-1], v[i]) > 0) {
+            ac.pop_back();
+        }
+        ac.emplace_back(v[i]);
+    }
+
+    for (int i = n - 1; i >= 0; i--) {
+        while (tmp.size() >= 2 && ccw(tmp.end()[-2], tmp.end()[-1], v[i]) > 0) {
+            tmp.pop_back();
+        }
+        tmp.emplace_back(v[i]);
+    }
+
+    ac.pop_back();
+    tmp.pop_back();
+
+    repv(i, tmp) {
+        ac.emplace_back(i);
+    }
+
+    return ac;
+}
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n;
+    cin >> n;
+    V<pt> a(n);
+    cin >> a;
+    auto conv = convex_hull(a);
+    cout << conv.size() << '\n';
+    repv(i, conv) {
+        cout << i.x << ' ' << i.y << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}
diff --git a/CSES Problem Set/Point Location Test.cpp b/CSES Problem Set/Point Location Test.cpp
new file mode 100644
index 0000000..37a9f87
--- /dev/null
+++ b/CSES Problem Set/Point Location Test.cpp	
@@ -0,0 +1,126 @@
+/* Problem URL: https://cses.fi/problemset/task/2189 */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int 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;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    ll x1, y1, x2, y2, x3, y3;
+    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
+
+    x3 -= x2;
+    y3 -= y2;
+    x2 -= x1;
+    y2 -= y1;
+
+    ll ar = x2 * y3 - y2 * x3;
+
+    if (ar > 0) {
+        cout << "LEFT\n";
+        return;
+    }
+
+    if (ar < 0) {
+        cout << "RIGHT\n";
+        return;
+    }
+
+    cout << "TOUCH\n";
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}
diff --git a/CSES Problem Set/Polygon Area.cpp b/CSES Problem Set/Polygon Area.cpp
new file mode 100644
index 0000000..41767ab
--- /dev/null
+++ b/CSES Problem Set/Polygon Area.cpp	
@@ -0,0 +1,122 @@
+/* Problem URL: https://cses.fi/problemset/task/2191 */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int 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;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    V<pair<ll, ll>> a(n);
+    repv(i, a) {
+        cin >> i.first >> i.second;
+    }
+
+    ll ar = 0;
+    rep(i, n) {
+        auto [x1, y1] = a[i];
+        auto [x2, y2] = a[(i + 1) % n];
+
+        ar += x1 * y2 - y1 * x2;
+    }
+
+    cout << abs(ar) << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}