Solved a bunch of problems

84 files changed, 1971 insertions, 0 deletions

diff --git a/contests/Round#849(Div4)/A/main b/contests/Round#849(Div4)/A/main
new file mode 100755
index 0000000..3e81677
--- /dev/null
+++ b/contests/Round#849(Div4)/A/main
diff --git a/contests/Round#849(Div4)/A/main.cpp b/contests/Round#849(Div4)/A/main.cpp
new file mode 100755
index 0000000..aa30531
--- /dev/null
+++ b/contests/Round#849(Div4)/A/main.cpp
@@ -0,0 +1,92 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<int, int>;
+using vpi = vector<pi>;
+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
+
+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};
+
+//pretty printing
+template<typename K, typename V>
+void printm(const map<K, V> &mp) {
+  cerr << "{" << endl;
+  for (auto p : mp) {
+    cerr << "  { " << p.first << " : " << p.second << " }\n";
+  }
+  cerr << "}" << endl;
+}
+template<typename T>
+void printv(const vector<T> &v) {
+  cerr << "[";
+  for (int i = 0; i < v.size(); i++) {
+    if (i == v.size() - 1) {
+      cerr << v[i];
+    } else {
+      cerr << v[i] << ", ";
+    }
+  }
+  cerr << "]\n";
+}
+
+template<typename T>
+void printvv(const vector<vector<T>> &v) {
+  cerr << "[\n";
+  for (auto &vec : v) {
+    cout << "  ";
+    printv(vec);
+  }
+  cerr << "]\n";
+}
+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() {
+  string haystack = "codeforces";
+  char ch;
+  cin >> ch;
+  cout << (count(all(haystack), ch) ? "YES" : "NO") << '\n';
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round#849(Div4)/A/main_input0.txt b/contests/Round#849(Div4)/A/main_input0.txt
new file mode 100644
index 0000000..9d71f59
--- /dev/null
+++ b/contests/Round#849(Div4)/A/main_input0.txt
@@ -0,0 +1,11 @@
+10
+a
+b
+c
+d
+e
+f
+g
+h
+i
+j
diff --git a/contests/Round#849(Div4)/A/main_output0.txt b/contests/Round#849(Div4)/A/main_output0.txt
new file mode 100644
index 0000000..6df8a46
--- /dev/null
+++ b/contests/Round#849(Div4)/A/main_output0.txt
@@ -0,0 +1,10 @@
+NO
+NO
+YES
+YES
+YES
+YES
+NO
+NO
+NO
+NO
diff --git a/contests/Round#849(Div4)/B/main b/contests/Round#849(Div4)/B/main
new file mode 100755
index 0000000..24928cb
--- /dev/null
+++ b/contests/Round#849(Div4)/B/main
diff --git a/contests/Round#849(Div4)/B/main.cpp b/contests/Round#849(Div4)/B/main.cpp
new file mode 100755
index 0000000..da40ca0
--- /dev/null
+++ b/contests/Round#849(Div4)/B/main.cpp
@@ -0,0 +1,122 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<int, int>;
+using vpi = vector<pi>;
+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
+
+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};
+
+//pretty printing
+template<typename K, typename V>
+void printm(const map<K, V> &mp) {
+  cerr << "{" << endl;
+  for (auto p : mp) {
+    cerr << "  { " << p.first << " : " << p.second << " }\n";
+  }
+  cerr << "}" << endl;
+}
+template<typename T>
+void printv(const vector<T> &v) {
+  cerr << "[";
+  for (int i = 0; i < v.size(); i++) {
+    if (i == v.size() - 1) {
+      cerr << v[i];
+    } else {
+      cerr << v[i] << ", ";
+    }
+  }
+  cerr << "]\n";
+}
+
+template<typename T>
+void printvv(const vector<vector<T>> &v) {
+  cerr << "[\n";
+  for (auto &vec : v) {
+    cout << "  ";
+    printv(vec);
+  }
+  cerr << "]\n";
+}
+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
+ */
+
+struct Point {
+  int x;
+  int y;
+  Point(int x, int y) {
+    this->x = x;
+    this->y = y;
+  }
+};
+
+void solve() {
+  Point p(0, 0);
+  int n;
+  cin >> n;
+  string str;
+  cin >> str;
+  for (auto ch: str) {
+    if(ch == 'U') {
+      p.y++;
+    }
+    else if(ch == 'D') {
+      p.y--;
+    }
+    else if(ch == 'R') {
+      p.x++;
+    }
+    else if(ch == 'L') {
+      p.x--;
+    }
+
+    if (p.x == 1 && p.y == 1) {
+      cout << "YES" << '\n';
+      return;
+    }
+  }
+  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/Round#849(Div4)/B/main_input0.txt b/contests/Round#849(Div4)/B/main_input0.txt
new file mode 100644
index 0000000..bca5a3e
--- /dev/null
+++ b/contests/Round#849(Div4)/B/main_input0.txt
@@ -0,0 +1,15 @@
+7
+7
+UUURDDL
+2
+UR
+8
+RRRUUDDD
+3
+LLL
+4
+DUUR
+5
+RUDLL
+11
+LLLLDDRUDRD
diff --git a/contests/Round#849(Div4)/B/main_output0.txt b/contests/Round#849(Div4)/B/main_output0.txt
new file mode 100644
index 0000000..4699a2d
--- /dev/null
+++ b/contests/Round#849(Div4)/B/main_output0.txt
@@ -0,0 +1,7 @@
+YES
+YES
+NO
+NO
+YES
+YES
+NO
diff --git a/contests/Round#849(Div4)/C/main b/contests/Round#849(Div4)/C/main
new file mode 100755
index 0000000..7f05022
--- /dev/null
+++ b/contests/Round#849(Div4)/C/main
diff --git a/contests/Round#849(Div4)/C/main.cpp b/contests/Round#849(Div4)/C/main.cpp
new file mode 100755
index 0000000..91c1a12
--- /dev/null
+++ b/contests/Round#849(Div4)/C/main.cpp
@@ -0,0 +1,105 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<int, int>;
+using vpi = vector<pi>;
+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
+
+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};
+
+//pretty printing
+template<typename K, typename V>
+void printm(const map<K, V> &mp) {
+  cerr << "{" << endl;
+  for (auto p : mp) {
+    cerr << "  { " << p.first << " : " << p.second << " }\n";
+  }
+  cerr << "}" << endl;
+}
+template<typename T>
+void printv(const vector<T> &v) {
+  cerr << "[";
+  for (int i = 0; i < v.size(); i++) {
+    if (i == v.size() - 1) {
+      cerr << v[i];
+    } else {
+      cerr << v[i] << ", ";
+    }
+  }
+  cerr << "]\n";
+}
+
+template<typename T>
+void printvv(const vector<vector<T>> &v) {
+  cerr << "[\n";
+  for (auto &vec : v) {
+    cout << "  ";
+    printv(vec);
+  }
+  cerr << "]\n";
+}
+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
+ */
+
+int countPairs(string &str) {
+  int cnt = 0;
+  for (int i = 0; i < str.length() / 2; i++) {
+    if (str[i] != str[str.length() - 1 - i]) {
+      cnt++;
+    } else {
+      break;
+    }
+  }
+  return cnt;
+}
+
+void solve() {
+  int n;
+  cin >> n;
+  string str;
+  cin >> str;
+  cout << str.length() - 2 * countPairs(str) << '\n';
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  while(tt--) {
+    solve();
+  }
+}
+
+
diff --git a/contests/Round#849(Div4)/C/main_input0.txt b/contests/Round#849(Div4)/C/main_input0.txt
new file mode 100644
index 0000000..b07910f
--- /dev/null
+++ b/contests/Round#849(Div4)/C/main_input0.txt
@@ -0,0 +1,19 @@
+9
+3
+100
+4
+0111
+5
+10101
+6
+101010
+7
+1010110
+1
+1
+2
+10
+2
+11
+10
+1011011010
diff --git a/contests/Round#849(Div4)/C/main_output0.txt b/contests/Round#849(Div4)/C/main_output0.txt
new file mode 100644
index 0000000..89375dd
--- /dev/null
+++ b/contests/Round#849(Div4)/C/main_output0.txt
@@ -0,0 +1,9 @@
+1
+2
+5
+0
+3
+1
+0
+2
+4
diff --git a/contests/Round#849(Div4)/D/main b/contests/Round#849(Div4)/D/main
new file mode 100755
index 0000000..b59f7cc
--- /dev/null
+++ b/contests/Round#849(Div4)/D/main
diff --git a/contests/Round#849(Div4)/D/main.cpp b/contests/Round#849(Div4)/D/main.cpp
new file mode 100755
index 0000000..9e9da38
--- /dev/null
+++ b/contests/Round#849(Div4)/D/main.cpp
@@ -0,0 +1,104 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<int, int>;
+using vpi = vector<pi>;
+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
+
+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};
+
+//pretty printing
+template<typename K, typename V>
+void printm(const map<K, V> &mp) {
+  cerr << "{" << endl;
+  for (auto p : mp) {
+    cerr << "  { " << p.first << " : " << p.second << " }\n";
+  }
+  cerr << "}" << endl;
+}
+template<typename T>
+void printv(const vector<T> &v) {
+  cerr << "[";
+  for (int i = 0; i < v.size(); i++) {
+    if (i == v.size() - 1) {
+      cerr << v[i];
+    } else {
+      cerr << v[i] << ", ";
+    }