Solved a couple of problem on codeforces

1 files changed, 172 insertions, 0 deletions

diff --git a/codeforces/LuckyNumbers/main.cpp b/codeforces/LuckyNumbers/main.cpp
new file mode 100755
index 0000000..90b029e
--- /dev/null
+++ b/codeforces/LuckyNumbers/main.cpp
@@ -0,0 +1,172 @@
+#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
+ */
+
+vi cache;
+
+
+int getLucky(int n) {
+  int mx = 0;
+  int mn = 10;
+  while(n) {
+    mx = max(mx, n % 10);
+    mn = min(mn, n % 10);
+    n /= 10;
+  }
+  return mx - mn;
+}
+
+void fillCache() {
+  for (int i = 0; i < 1e6 + 3; i++) {
+    if (getLucky(i) == 9) {
+      cache.pb(i);
+    }
+  }
+}
+
+void solve() {
+  int l, r;
+  cin >> l >> r;
+  pii ans = {0, 0};
+  if (r - l >= 100) {
+    for (auto x : cache) {
+      if (x >= l && x <= r) {
+        cout << x << '\n';
+        return;
+      }
+    }
+  }
+  for (int i = l; i <= r; i++) {
+    int luck = getLucky(i);
+    if (luck >= ans.first) {
+      ans = {luck, i};
+    }
+  }
+  cout << ans.second << '\n';
+}
+
+int main () {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
+  int tt;
+  cin >> tt;
+  fillCache();
+  while(tt--) {
+    solve();
+  }
+}
+
+