test/aoj/2955/main.test.cpp

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• Last update: 2021-04-23 23:44:44+09:00
• Problem: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2955

Depends on

• Union-find (Mylib/DataStructure/UnionFind/unionfind.cpp)
• Input vector (Mylib/IO/input_vector.cpp)
• Subset sum problem (With quantity limitations) (Mylib/Typical/subset_sum_limited.cpp)

Code

#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2955"

#include <iostream>
#include <map>
#include <vector>
#include "Mylib/DataStructure/UnionFind/unionfind.cpp"
#include "Mylib/IO/input_vector.cpp"
#include "Mylib/Typical/subset_sum_limited.cpp"

namespace hl = haar_lib;

int main() {
  int N, R;
  std::cin >> N >> R;

  auto p = hl::input_vector<int>(N);
  for (auto &x : p) x -= 1;

  hl::unionfind uf(N);

  for (int i = 0; i < N; ++i) {
    uf.merge(i, p[i]);
  }

  std::map<int, int> cycles;
  for (int i = 0; i < N; ++i) {
    if (i == uf.root_of(i)) cycles[uf.size_of(i)] += 1;
  }

  std::vector<int> a, m;
  for (auto &[k, v] : cycles) {
    a.push_back(k);
    m.push_back(v);
  }

  bool ans = hl::subset_sum_limited(a.size(), R, a, m)[R];

  std::cout << (ans ? "Yes" : "No") << std::endl;

  return 0;
}

#line 1 "test/aoj/2955/main.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2955"

#include <iostream>
#include <map>
#include <vector>
#line 2 "Mylib/DataStructure/UnionFind/unionfind.cpp"
#include <algorithm>
#include <numeric>
#line 5 "Mylib/DataStructure/UnionFind/unionfind.cpp"

namespace haar_lib {
  class unionfind {
    int n_, count_;
    mutable std::vector<int> parent_;
    std::vector<int> depth_, size_;

  public:
    unionfind() {}
    unionfind(int n) : n_(n), count_(n), parent_(n), depth_(n, 1), size_(n, 1) {
      std::iota(parent_.begin(), parent_.end(), 0);
    }

    int root_of(int i) const {
      if (parent_[i] == i)
        return i;
      else
        return parent_[i] = root_of(parent_[i]);
    }

    bool is_same(int i, int j) const { return root_of(i) == root_of(j); }

    int merge(int i, int j) {
      const int ri = root_of(i), rj = root_of(j);
      if (ri == rj)
        return ri;
      else {
        --count_;
        if (depth_[ri] < depth_[rj]) {
          parent_[ri] = rj;
          size_[rj] += size_[ri];
          return rj;
        } else {
          parent_[rj] = ri;
          size_[ri] += size_[rj];
          if (depth_[ri] == depth_[rj]) ++depth_[ri];
          return ri;
        }
      }
    }

    int size_of(int i) const { return size_[root_of(i)]; }

    int count_groups() const { return count_; }

    auto get_groups() const {
      std::vector<std::vector<int>> ret(n_);

      for (int i = 0; i < n_; ++i) {
        ret[root_of(i)].push_back(i);
      }

      ret.erase(
          std::remove_if(
              ret.begin(), ret.end(),
              [](const auto &a) { return a.empty(); }),
          ret.end());

      return ret;
    }
  };
}  // namespace haar_lib
#line 4 "Mylib/IO/input_vector.cpp"

namespace haar_lib {
  template <typename T>
  std::vector<T> input_vector(int N) {
    std::vector<T> ret(N);
    for (int i = 0; i < N; ++i) std::cin >> ret[i];
    return ret;
  }

  template <typename T>
  std::vector<std::vector<T>> input_vector(int N, int M) {
    std::vector<std::vector<T>> ret(N);
    for (int i = 0; i < N; ++i) ret[i] = input_vector<T>(M);
    return ret;
  }
}  // namespace haar_lib
#line 2 "Mylib/Typical/subset_sum_limited.cpp"
#include <cassert>
#line 4 "Mylib/Typical/subset_sum_limited.cpp"

namespace haar_lib {
  auto subset_sum_limited(int N, int K, const std::vector<int> &a, const std::vector<int> &m) {
    assert((int) a.size() == N and (int) m.size() == N);
    std::vector<int> dp(K + 1, -1);

    dp[0] = 0;
    for (int i = 0; i < N; ++i) {
      for (int j = 0; j <= K; ++j) {
        if (dp[j] >= 0) {
          dp[j] = m[i];
        } else if (j < a[i] or dp[j - a[i]] <= 0) {
          dp[j] = -1;
        } else {
          dp[j] = dp[j - a[i]] - 1;
        }
      }
    }

    for (int i = 0; i <= K; ++i) dp[i] = dp[i] >= 0;

    return dp;
  }
}  // namespace haar_lib
#line 9 "test/aoj/2955/main.test.cpp"

namespace hl = haar_lib;

int main() {
  int N, R;
  std::cin >> N >> R;

  auto p = hl::input_vector<int>(N);
  for (auto &x : p) x -= 1;

  hl::unionfind uf(N);

  for (int i = 0; i < N; ++i) {
    uf.merge(i, p[i]);
  }

  std::map<int, int> cycles;
  for (int i = 0; i < N; ++i) {
    if (i == uf.root_of(i)) cycles[uf.size_of(i)] += 1;
  }

  std::vector<int> a, m;
  for (auto &[k, v] : cycles) {
    a.push_back(k);
    m.push_back(v);
  }

  bool ans = hl::subset_sum_limited(a.size(), R, a, m)[R];

  std::cout << (ans ? "Yes" : "No") << std::endl;

  return 0;
}

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