Removed some empty *.cpp files and Solved some new problems

21 files changed, 970 insertions, 0 deletions

diff --git a/contests/Round862/A/main b/contests/Round862/A/main
new file mode 100755
index 0000000..f58e479
--- /dev/null
+++ b/contests/Round862/A/main
diff --git a/contests/Round862/A/main.cpp b/contests/Round862/A/main.cpp
new file mode 100755
index 0000000..439022f
--- /dev/null
+++ b/contests/Round862/A/main.cpp
@@ -0,0 +1,153 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b) - 1) / (b))
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const unordered_map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const unordered_set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+void print() {
+  cerr << "\n";
+}
+
+template<typename T, typename... TS>
+void print(T val, TS... vals) {
+  cerr << val << " ";
+  print(vals...);
+}
+
+
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+void solve() {
+  int n;
+  cin >> n;
+  vi v(n);
+  for (auto &x : v) {
+   cin >> x;
+  }
+  for (int i = 0; i < (1 << 8); i++) {
+    vi b(n);
+    int x = 0;
+    for (int j = 0; j < n; j++) {
+      b[j] = v[j] ^ i;
+      x ^= b[j];
+    }
+    if (x == 0) {
+      cout << i << '\n';
+      return;
+    }
+  }
+  cout << -1 << '\n';
+
+
+
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round862/A/main_input0.txt b/contests/Round862/A/main_input0.txt
new file mode 100644
index 0000000..a5980e2
--- /dev/null
+++ b/contests/Round862/A/main_input0.txt
@@ -0,0 +1,11 @@
+5
+3
+1 2 5
+3
+1 2 3
+4
+0 1 2 3
+4
+1 2 2 3
+1
+1
diff --git a/contests/Round862/A/main_output0.txt b/contests/Round862/A/main_output0.txt
new file mode 100644
index 0000000..c731a0f
--- /dev/null
+++ b/contests/Round862/A/main_output0.txt
@@ -0,0 +1,5 @@
+6
+0
+3
+-1
+1
diff --git a/contests/Round862/B/main b/contests/Round862/B/main
new file mode 100755
index 0000000..e47f442
--- /dev/null
+++ b/contests/Round862/B/main
diff --git a/contests/Round862/B/main.cpp b/contests/Round862/B/main.cpp
new file mode 100755
index 0000000..b256f22
--- /dev/null
+++ b/contests/Round862/B/main.cpp
@@ -0,0 +1,159 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b) - 1) / (b))
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const unordered_map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const unordered_set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+void print() {
+  cerr << "\n";
+}
+
+template<typename T, typename... TS>
+void print(T val, TS... vals) {
+  cerr << val << " ";
+  print(vals...);
+}
+
+
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+void solve() {
+  int n;
+  cin >> n;
+  string s;
+  cin >> s;
+  map<char, int> mp;
+  string alphabet = "abcdefghijklmnopqrstuvwxyz";
+  for (int i = 0; i < n; i++) {
+    mp[s[i]] = i;
+  }
+  string ans = "";
+  int pos = find(all(alphabet), s[0]) - alphabet.begin();
+  for (int i = 0; i <= pos; i++) {
+    if (mp[alphabet[i]] != 0) {
+      ans += alphabet[i];
+      for (int j = 0; j < n; j++) {
+        if (j != mp[alphabet[i]]) {
+          ans += s[j];
+        }
+      }
+      break;
+    }
+  }
+  if (ans == "") {
+    cout << s << '\n';
+  } else {
+    cout << ans << '\n';
+  }
+
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round862/B/main_input0.txt b/contests/Round862/B/main_input0.txt
new file mode 100644
index 0000000..8b27b3c
--- /dev/null
+++ b/contests/Round862/B/main_input0.txt
@@ -0,0 +1,9 @@
+4
+3
+cba
+4
+acac
+5
+abbcb
+4
+aaba
diff --git a/contests/Round862/B/main_input1.txt b/contests/Round862/B/main_input1.txt
new file mode 100644
index 0000000..260e893
--- /dev/null
+++ b/contests/Round862/B/main_input1.txt
@@ -0,0 +1,3 @@
+1
+6
+abbaab
\ No newline at end of file
diff --git a/contests/Round862/B/main_output0.txt b/contests/Round862/B/main_output0.txt
new file mode 100644
index 0000000..d872337
--- /dev/null
+++ b/contests/Round862/B/main_output0.txt
@@ -0,0 +1,4 @@
+acb
+aacc
+abbcb
+aaab
diff --git a/contests/Round862/B/main_output1.txt b/contests/Round862/B/main_output1.txt
new file mode 100644
index 0000000..b3be43d
--- /dev/null
+++ b/contests/Round862/B/main_output1.txt
@@ -0,0 +1 @@
+aabbab
\ No newline at end of file
diff --git a/contests/Round862/C/main b/contests/Round862/C/main
new file mode 100755
index 0000000..6688851
--- /dev/null
+++ b/contests/Round862/C/main
diff --git a/contests/Round862/C/main.cpp b/contests/Round862/C/main.cpp
new file mode 100755
index 0000000..edb19ce
--- /dev/null
+++ b/contests/Round862/C/main.cpp
@@ -0,0 +1,176 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const unordered_map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const unordered_set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+void print() {
+  cerr << "\n";
+}
+
+template<typename T, typename... TS>
+void print(T val, TS... vals) {
+  cerr << val << " ";
+  print(vals...);
+}
+
+
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+ll mySqrt(ll n) {
+  ll l = 1, r = sqrt(n) + 4;
+  while (l <= r) {
+    ll mid = (l + r) / 2;
+    if (mid * mid <= n) {
+      l = mid + 1;
+    } else {
+      r = mid - 1;
+    }
+  }
+  return l - 1;
+}
+
+void solve() {
+  int n, m;
+  cin >> n >> m;
+  vi lines(n);
+  for (int i = 0; i < n; ++i) {
+    cin >> lines[i];
+  }
+  sort(all(lines));
+  for (int i = 0; i < m; ++i) {
+    ll a, b, c;
+    cin >> a >> b >> c;
+    if (c <= 0) {
+      cout << "NO\n";
+      continue;
+    }
+    ll ac4 = 4LL * a * c;
+    ac4 = mySqrt(ac4);
+    if (ac4 * ac4 != 4 * a * c) {
+      ac4++;
+    }
+    ll toFindL = b - ac4;
+    ll toFindR = b + ac4;
+    int l = ub(all(lines), toFindL) - lines.begin();
+    if (l != n) {
+      if (lines[l] < toFindR) {
+        cout << "YES\n";
+        cout << lines[l] << '\n';
+      } else {
+        cout << "NO\n";
+      }
+    } else {
+      cout << "NO\n";
+    }
+  }
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round862/C/main_input0.txt b/contests/Round862/C/main_input0.txt
new file mode 100644
index 0000000..097b096
--- /dev/null
+++ b/contests/Round862/C/main_input0.txt
@@ -0,0 +1,22 @@
+5
+1 2
+1
+1 -1 2
+1 -1 3
+2 2
+1
+4
+1 2 1
+2 5 1
+1 1
+0
+1 0 0
+1 1
+100000000
+100000000 100000000 100000000
+2 3
+0
+2
+2 2 1
+1 -2 1
+1 -2 -1
diff --git a/contests/Round862/C/main_input1.txt b/contests/Round862/C/main_input1.txt
new file mode 100644
index 0000000..e6b2ff6
--- /dev/null
+++ b/contests/Round862/C/main_input1.txt
@@ -0,0 +1,4 @@
+1
+1 1
+0
+4 2 1
\ No newline at end of file
diff --git a/contests/Round862/C/main_input2.txt b/contests/Round862/C/main_input2.txt
new file mode 100644
index 0000000..b6984a2
--- /dev/null
+++ b/contests/Round862/C/main_input2.txt
@@ -0,0 +1,4 @@
+1
+1 1
+0
+5 2 1
\ No newline at end of file
diff --git a/contests/Round862/C/main_output0.txt b/contests/Round862/C/main_output0.txt
new file mode 100644
index 0000000..ed2b9fd
--- /dev/null
+++ b/contests/Round862/C/main_output0.txt
@@ -0,0 +1,19 @@
+YES
+1
+YES
+1
+
+YES
+1
+YES
+4
+
+NO
+
+YES
+100000000
+
+YES
+0
+NO
+NO
diff --git a/contests/Round862/C/main_output1.txt b/contests/Round862/C/main_output1.txt
new file mode 100644
index 0000000..2501d40
--- /dev/null
+++ b/contests/Round862/C/main_output1.txt
@@ -0,0 +1,2 @@
+YES
+0
\ No newline at end of file
diff --git a/contests/Round862/C/main_output2.txt b/contests/Round862/C/main_output2.txt
new file mode 100644
index 0000000..2501d40
--- /dev/null
+++ b/contests/Round862/C/main_output2.txt
@@ -0,0 +1,2 @@
+YES
+0
\ No newline at end of file
diff --git a/contests/Round862/D/main.cpp b/contests/Round862/D/main.cpp
new file mode 100755
index 0000000..70c7757
--- /dev/null
+++ b/contests/Round862/D/main.cpp
@@ -0,0 +1,132 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b) - 1) / (b))
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const unordered_map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const unordered_set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+void print() {
+  cerr << "\n";
+}
+
+template<typename T, typename... TS>
+void print(T val, TS... vals) {
+  cerr << val << " ";
+  print(vals...);
+}
+
+
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+void solve() {
+
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round862/E/main.cpp b/contests/Round862/E/main.cpp
new file mode 100755
index 0000000..70c7757
--- /dev/null
+++ b/contests/Round862/E/main.cpp
@@ -0,0 +1,132 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b) - 1) / (b))
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const unordered_map<K, V>& m) {
+  os << "{";
+  for (const auto& p : m) {
+    os << p.first << ": " << p.second << ", ";
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const unordered_set<T>& s) {
+  int i = 0;
+  os << "{";
+  for (const auto& e : s) {
+    if (i > 0) os << ", ";
+    os << e;
+    i++;
+  }
+  os << "}";
+  return os;
+}
+
+void print() {
+  cerr << "\n";
+}
+
+template<typename T, typename... TS>
+void print(T val, TS... vals) {
+  cerr << val << " ";
+  print(vals...);
+}
+
+
+
+/* stuff you should look for:
+  ---------------------------
+   * special cases (n=1?)
+   * int overflow, array bounds
+   * do smth instead of nothing and stay organized
+   * WRITE STUFF DOWN
+   * DON'T GET STUCK ON ONE APPROACH
+ */
+
+void solve() {
+
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round862/F/main.cpp b/contests/Round862/F/main.cpp
new file mode 100755
index 0000000..70c7757
--- /dev/null
+++ b/contests/Round862/F/main.cpp
@@ -0,0 +1,132 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pii = pair<int, int>;
+using vpi = vector<pii>;
+using vi = vector<int>;
+using vll = vector<long long>;
+using mpii = map<int, int>;
+using mpll = map<ll, ll>;
+using db = long double;
+
+#define pb push_back 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define lb lower_bound
+#define ub upper_bound
+#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
+#define ceil(a, b) ((a) + (b) - 1) / (b))
+
+const int MOD = (int)1e9 + 7;
+const db PI = acos((db)-1);
+const int dx[4]{1, 0, -1, 0};
+const int dy[4]{0, 1, 0, -1};
+
+template<typename K, typename V> ostream& operator<<(ostream& os, const pair<K, V>& p);
+template<typename T> ostream& operator<<(ostream& os, const vector<T>& vec);
+template<typename K, typename V> ostream& operator<<(ostream& os, const map<K, V>& m);
+template<typename K, typename V> ostream& operator<<(ostream& os, const unordered_map<K, V>& m);
+template<typename T> ostream& operator<<(ostream& os, const set<T>& s);
+template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s);
+
+template<typename K, typename V>
+ostream& operator<<(ostream& os, const pair<K, V>& p) {
+  os << "(" << p.first << ", " << p.second << ")";
+  return os;
+}
+
+template<typename T>
+ostream& operator<<(ostream& os, const vector<T>& vec) {
+  os << "{";
+  for (size_t i = 0; i < vec.size(); ++i) {
+    if (i > 0) os << ", ";
+    os << vec[i];
+  }
+  os << "}";
+  return os;
+}
+
+
+template<typename K, typename V></