結果

問題 No.1668 Grayscale
コンテスト
ユーザー keijak
提出日時 2021-09-03 23:49:31
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
WA  
実行時間 -
コード長 4,995 bytes
コンパイル時間 2,682 ms
コンパイル使用メモリ 209,996 KB
最終ジャッジ日時 2025-01-24 07:24:20
ジャッジサーバーID
（参考情報） 		judge1 / judge5
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 7 WA * 15
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
#define REP_(i, a_, b_, a, b, ...) \
  for (int i = (a), END_##i = (b); i < END_##i; ++i)
#define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define ALL(x) std::begin(x), std::end(x)
using i64 = long long;

template<typename T, typename U>
inline bool chmax(T &a, U b) {
  return a < b and ((a = std::move(b)), true);
}
template<typename T, typename U>
inline bool chmin(T &a, U b) {
  return a > b and ((a = std::move(b)), true);
}
template<typename T>
inline int ssize(const T &a) {
  return (int) std::size(a);
}

template<typename T>
std::istream &operator>>(std::istream &is, std::vector<T> &a) {
  for (auto &x: a) is >> x;
  return is;
}
template<typename T, typename U>
std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &a) {
  return os << "(" << a.first << ", " << a.second << ")";
}
template<typename Container>
std::ostream &print_seq(const Container &a, std::string_view sep = " ",
                        std::string_view ends = "\n",
                        std::ostream &os = std::cout) {
  auto b = std::begin(a), e = std::end(a);
  for (auto it = std::begin(a); it != e; ++it) {
    if (it != b) os << sep;
    os << *it;
  }
  return os << ends;
}
template<typename T, typename = void>
struct is_iterable : std::false_type {};
template<typename T>
struct is_iterable<T, std::void_t<decltype(std::begin(std::declval<T>())),
                                  decltype(std::end(std::declval<T>()))>>
    : std::true_type {
};

template<typename T, typename = std::enable_if_t<
    is_iterable<T>::value &&
        !std::is_same<T, std::string_view>::value &&
        !std::is_same<T, std::string>::value>>
std::ostream &operator<<(std::ostream &os, const T &a) {
  return print_seq(a, ", ", "", (os << "{")) << "}";
}

void print() { std::cout << "\n"; }
template<class T>
void print(const T &x) {
  std::cout << x << "\n";
}
template<typename Head, typename... Tail>
void print(const Head &head, Tail... tail) {
  std::cout << head << " ";
  print(tail...);
}

struct Input {
  template<typename T>
  operator T() const {
    T x;
    std::cin >> x;
    return x;
  }
} in;

#ifdef MY_DEBUG
#include "debug_dump.hpp"
#else
#define DUMP(...)
#endif

using namespace std;

// s |= t;
// Merges two sets into their union.
// The first argument will be updated to the result.
template<typename T>
std::set<T> &operator|=(std::set<T> &s, const std::set<T> &t) {
  s.insert(t.begin(), t.end());
  return s;
}
template<typename T>
std::set<T> &operator|=(std::set<T> &s, std::set<T> &&t) {
  if (s.size() >= t.size()) {
    s.merge(t);
  } else {
    t.merge(s);
    s.swap(t);
  }
  return s;
}

struct UnionFind {
  int n;
  mutable std::vector<int> parent;  // positive: parent, negative: size
  std::set<int> roots_;
  std::vector<set<int>> agg_data_;

  explicit UnionFind(std::vector<set<int>> data)
      : n(data.size()), parent(data.size(), -1), agg_data_(move(data)) {
    for (int i = 0; i < n; ++i) roots_.insert(i);
  }

  bool unite(int x, int y) {
    x = find(x), y = find(y);
    if (x == y) return false;
    if (-parent[x] < -parent[y]) std::swap(x, y);
    parent[x] += parent[y];
    parent[y] = x;
    agg_data_[x] |= agg_data_[y];
    roots_.erase(y);
    return true;
  }

  int find(int v) const {
    if (parent[v] < 0) return v;
    return parent[v] = find(parent[v]);
  }

  int size(int v) const { return -parent[find(v)]; }

  bool same(int x, int y) const { return find(x) == find(y); }

  const std::set<int> &roots() const { return roots_; }
};

auto solve() {
  const int H = in, W = in, N = in;
  vector C(H, vector(W, 0));
  REP(i, H) {
    REP(j, W) {
      C[i][j] = in;
    }
    DUMP(C[i]);
  }
  vector mi(H, vector(W, 1));
  vector md(H, vector(W, 1));
  vector dp(2, vector(H, vector(W, 1)));
  vector done(2, vector(H, vector(W, 0)));

  auto inside = [&](int i, int j) -> bool {
    return (0 <= i and i < H and 0 <= j and j < W);
  };
  vector<int> dx = {0, -1, 0, 1};
  vector<int> dy = {1, 0, -1, 0};

  auto dfs = [&](auto &rec, int i, int j, bool inc) -> void {
    REP(d, 4) {
      int ni = i + dx[d];
      int nj = j + dy[d];
      if (not inside(ni, nj)) continue;
      if (inc and C[i][j] > C[ni][nj]) continue;
      if (not inc and C[i][j] < C[ni][nj]) continue;
      if (not done[inc][ni][nj]) {
        done[inc][ni][nj] = true;
        rec(rec, ni, nj, inc);
      }
      int b = (C[i][j] == C[ni][nj]) ? 0 : 1;
      chmax(dp[inc][i][j], dp[inc][ni][nj] + b);
    }
  };
  int ans = 1;
  REP(i, H) REP(j, W) REP(inc, 2) {
        if (not done[inc][i][j]) {
          done[inc][i][j] = true;
          dfs(dfs, i, j, inc);
        }
        chmax(ans, dp[inc][i][j]);
      }

  REP(inc, 2) {
    DUMP(inc);
    REP(i, H) DUMP(dp[inc][i]);
  }
  return ans;
}

int main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);
  cout << std::fixed << std::setprecision(18);
  const int t = 1;
  REP(test_case, t) {
    auto ans = solve();
    print(ans);
  }
}
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