feat(codeforces): 799

codeforces/799/d.cc

@@ -0,0 +1,74 @@
+#include <bits/stdc++.h>  // {{{
+
+// https://codeforces.com/blog/entry/96344
+
+#pragma GCC optimize("O2,unroll-loops")
+#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
+
+using namespace std;
+
+#define prln(...) std::println(__VA_ARGS__)
+#define pr(...) std::print(__VA_ARGS__)
+
+#ifdef LOCAL
+#define dbgln(...) std::println(__VA_ARGS__)
+#define dbg(...) std::print(__VA_ARGS__)
+#else
+#define dbgln(...)
+#define dbg(...)
+#endif
+//  }}}
+
+bitset<1441> seen;
+void solve() {
+  string s;
+  int x;
+  cin >> s >> x;
+  int start = stoi(s.substr(0, 2)) * 60 + stoi(s.substr(3, 2));
+  seen.reset();
+  int ans = 0;
+  auto is_palindrome = [&](string const& S) {
+    int l = 0, r = S.size() - 1;
+
+    while (l < r) {
+      if (S[l++] != S[r--])
+        return false;
+    }
+
+    return true;
+  };
+  auto mutate = [&](int time) {
+    int hour = time / 60;
+    string hour_part = to_string(hour);
+    if (hour_part.size() == 1)
+      hour_part = "0" + hour_part;
+    int minute = time % 60;
+    string minute_part = to_string(minute);
+    if (minute_part.size() == 1)
+      minute_part = "0" + minute_part;
+    return hour_part + ":" + minute_part;
+  };
+  while (!seen[start]) {
+    if (is_palindrome(s))
+      ++ans;
+    seen[start] = true;
+    start = (start + x) % 1440;
+    s = mutate(start);
+  }
+  cout << ans << '\n';
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit);
+
+  int tc = 1;
+  cin >> tc;
+
+  for (int t = 0; t < tc; ++t) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}