feat: 928

codeforces/928/g.cc

@@ -0,0 +1,105 @@
+#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;
+
+using i32 = int32_t;
+using u32 = uint32_t;
+using i64 = int64_t;
+using u64 = uint64_t;
+using f64 = double;
+using f128 = long double;
+
+#if __cplusplus >= 202002L
+template <typename T>
+constexpr T MIN = std::numeric_limits<T>::min();
+
+template <typename T>
+constexpr T MAX = std::numeric_limits<T>::max();
+
+template <typename T>
+[[nodiscard]] static T sc(auto&& x) {
+  return static_cast<T>(x);
+}
+
+template <typename T>
+[[nodiscard]] static T sz(auto&& x) {
+  return static_cast<T>(x.size());
+}
+#endif
+
+static void NO() {
+  std::cout << "NO\n";
+}
+
+static void YES() {
+  std::cout << "YES\n";
+}
+
+template <typename T>
+using vec = std::vector<T>;
+
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define ff first
+#define ss second
+
+#ifdef LOCAL
+#define db(...) std::print(__VA_ARGS__)
+#define dbln(...) std::println(__VA_ARGS__)
+#else
+#define db(...)
+#define dbln(...)
+#endif
+//  }}}
+
+void solve() {
+  u32 n;
+  cin >> n;
+  vec<vec<u32>> tree(n + 1);
+  for (u32 i = 2; i <= n; ++i) {
+    u32 a;
+    cin >> a;
+    tree[i].push_back(a);
+    tree[a].push_back(i);
+  }
+  string s;
+  cin >> s;
+  s = ' ' + s;
+
+  auto dfs = [&](auto&& self, u32 u, u32 p) -> vec<u32> {
+    vec<u32> dp(2);
+    dp[0] = (s[u] == 'P') ? 1 << 30 : 0;
+    dp[1] = (s[u] == 'S') ? 1 << 30 : 0;
+    for (u32 v : tree[u]) {
+      if (v == p)
+        continue;
+      auto prev = self(self, v, u);
+      dp[0] += min(prev[0], prev[1] + 1);
+      dp[1] += min(prev[1], prev[0] + 1);
+    }
+    return dp;
+  };
+
+  auto ans = dfs(dfs, 1, 0);
+  cout << *min_element(all(ans)) << '\n';
+}
+
+int main() {  // {{{
+  cin.tie(nullptr)->sync_with_stdio(false);
+  cin.exceptions(cin.failbit);
+
+  u32 tc = 1;
+  cin >> tc;
+
+  for (u32 t = 0; t < tc; ++t) {
+    solve();
+  }
+
+  return 0;
+}
+// }}}