链接：https://codeforces.com/gym/104065

A

#include "bits/stdc++.h"

using namespace std;

using i64 = long long;

constexpr int N = 2E5;

bool vis[N + 10][11][11];
int ans[N + 10][11][11];

void solve() {
  for (int i = 0; i <= N + 1; i++) {
    for (int j = 0; j < 11; j++) {
      for (int k = 0; k < 11; k++) {
        ans[i][j][k] = -1E9;
      }
    }
  }
  int n, m;
  cin >> n >> m;
  vector<int> a(n + 1), b(n + 1);
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; i++) {
    cin >> b[i];
  }
  sort(a.begin(), a.end());
  sort(b.begin(), b.end());
  function<int(int, int, int, int)> dfs = [&](int nowa, int nowb, int picka, int pickb) {  
    if (min(nowa, picka) == 0 && min(nowb, pickb) == 0) {
      return 0;
    }
    if (vis[nowa + nowb][picka][pickb]) {
      return ans[nowa + nowb][picka][pickb];
    }
    vis[nowa + nowb][picka][pickb] = 1;
    if (nowa > 0 && picka > 0) {
      int A = 1E9, B = 1E9;
      if (nowa > 1) {
        A = dfs(nowa - 2, nowb, picka - 1, pickb) + a[nowa];
      }
      if (nowb > 0 && pickb > 0) {
        B = dfs(nowa - 1, nowb - 1, picka - 1, pickb - 1) + a[nowa] - b[nowb];
      }  
      ans[nowa + nowb][picka][pickb] = max(ans[nowa + nowb][picka][pickb], min(A, B));      
    }
    if (nowb > 0) {
      int A = 1E9, B = 1E9;      
      if (nowb > 1 && pickb > 0) {
        A = dfs(nowa, nowb - 2, picka, pickb - 1) - b[nowb - 1];
      }
      if (nowa > 0) {
        B = dfs(nowa - 1, nowb - 1, picka, pickb);
      }
      ans[nowa + nowb][picka][pickb] = max(ans[nowa + nowb][picka][pickb], min(A, B));      
    }
    return ans[nowa + nowb][picka][pickb];
  };
  int ans = dfs(n, n, m, m);
  cout << ans << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
    solve();
  }
  return 0;
}

C

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

void solve() {
  int n;
  cin >> n;
  vector<vector<int>> g(n + 1);
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  i64 ans = 0;
  for (auto nex : g[1]) {
    i64 res = 0;
    function<void(int, int, i64)> dfs = [&](int cur, int pre, i64 dep) {
      res = max(res, dep);
      for (auto nex : g[cur]) {
        if (nex != pre) {
          dfs(nex, cur, dep + 1);
        }
      }
    };
    dfs(nex, 1, 1);
    ans += res;
  }
  cout << ans << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
    solve();
  }
  return 0;
}

G

#include "bits/stdc++.h"

using namespace std;

using i64 = long long;

void solve() {
  int n;
  cin >> n;
  vector<int> tmp(n);
  for (int i = 0; i < n; i++) {
    cin >> tmp[i];
  }
  int ans = 0;
  int tmpn = n;
  while (1) {
    int SIZE = tmp.size();
    if (SIZE == 1) {
      break;
    }
    vector<int> p;
    for (int i = 0; i < SIZE; i++) {
      if (i == 0) {
        if (tmp[i + 1] < tmp[i]) {
          p.push_back(tmp[i]);
        }
      } else if (i == SIZE - 1) {
        if (tmp[i - 1] < tmp[i]) {
          p.push_back(tmp[i]);
        }
      } else {
        if (tmp[i + 1] < tmp[i] && tmp[i - 1] < tmp[i]) {
          p.push_back(tmp[i]);
        }
      }
    }
    tmp = p;
    ans++;
  }
  cout << ans << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
    solve();
  }
  return 0;
}

H

#include "bits/stdc++.h"

using namespace std;

using i64 = long long;

void solve() {
  int n;
  cin >> n;
  n = 2 * n - 1;
  cout << n << '\n';
  for (int i = 1; i <= n; i++) {
    cout << i << " " << i << '\n';
  }
  cout << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
    solve();
  }
  return 0;
}

M

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

//constexpr int M = 998244353;
//constexpr int M = 1000000007;

void solve() {
  string s;
  cin >> s;
  int n;
  n = s.size();
  auto check = [&](char ch, char ch1) {
    if (ch1 == 'S' && ch == 'P') {
      return 1; 
    } 
    if (ch1 == 'R' && ch == 'S') {
      return 1;
    }
    if (ch1 == 'P' && ch == 'R') {
      return 1;
    }
    return 0;
  };
  vector<int> st;
  for (int i = 0; i < n; i++) {
    while (!st.empty() && check(s[st.back()], s[i])) {
      st.pop_back();
    }
    st.push_back(i);
  }
  cout << s[st[0]] << endl;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cout << fixed << setprecision(6);
  int tt = 1;
  cin >> tt;
  for (int _ = 1; _ <= tt; _++) {
    solve();
  }
  return 0;
}