Submission #24270

#	Time	Username	Problem	Language	Result	Execution time	Memory
24270		jiaqiyang	Cultivation (JOI17_cultivation)	C++14	100 / 100	1966 ms	3996 KiB

cultivation

#include <cstdio>
#include <climits>
#include <vector>
#include <algorithm>

typedef long long i64;

const int N = 300 + 10;

int r, c, n;

struct Point {
  int x, y;
  inline bool operator< (const Point &rhs) const {
    return x < rhs.x || (x == rhs.x && y < rhs.y);
  }
} p[N];

struct Info {
  int a, b, c;
  Info() { a = b = c = 0; }
  Info(int _a, int _b, int _c): a(_a), b(_b), c(_c) {}
} f[N][N];

void init(int l) {
  static int cur[N];
  int tot = 0;
  for (int r = l; r <= n; ++r) {
    int k = std::lower_bound(cur, cur + tot, p[r].y) - cur;
    cur[tot] = p[r].y;
    std::rotate(cur + k, cur + tot, cur + tot + 1);
    f[l][r].a = cur[0] - 1;
    f[l][r].b = c - cur[tot++];
    for (int i = 1; i < tot; ++i) f[l][r].c = std::max(f[l][r].c, cur[i] - cur[i - 1] - 1);
  }
}

class Queue {
  std::pair<int, int> q[4 * N];
  int f, r;
 public:
  void clear() {
    f = 1;
    r = 0;
  }
  void trim(int s) {
    while (f <= r && q[f].first < s) ++f;
  }
  void push(int x, int y) {
    while (f <= r && q[r].second <= y) --r;
    q[++r] = std::make_pair(x, y);
  }
  inline int front() const { return q[f].second; }
};

int ans;

void solve(int len) {
  static Info info[4 * N];
  static i64 pool[4 * N], temp[4 * N];
  for (int i = 1; i <= n; ++i) {
    pool[i] = p[i].x;
    pool[i + n] = p[i].x + len + 1;
  }
  std::merge(pool + 1, pool + n + 1, pool + n + 1, pool + 2 * n + 1, temp + 1);
  std::copy(temp + 1, temp + 2 * n + 1, pool + 1);
  int tot = std::unique(pool + 1, pool + 2 * n + 1) - pool - 1;
  for (int i = 1, l = 1, r = 1; i <= tot; ++i) {
    while (l <= n && !(p[l].x <= pool[i] && pool[i] <= (i64)p[l].x + len)) ++l;
    for (r = std::max(l, r); r <= n && p[r].x <= pool[i] && pool[i] <= (i64)p[r].x + len;) ++r;
    info[i] = (l > n ? Info(INT_MAX, INT_MAX, INT_MAX) : f[l][r - 1]);
  }
  static Queue q[3];
  q[0].clear(), q[1].clear(), q[2].clear();
  for (int i = 1, j = 1; i <= tot; ++i) {
    i64 s = pool[i];
    q[0].trim(i), q[1].trim(i), q[2].trim(i);
    for (; j <= tot && pool[j] <= s + r - 1; ++j) q[0].push(j, info[j].a), q[1].push(j, info[j].b), q[2].push(j, info[j].c);
    i64 cur = std::max(q[0].front() + q[1].front(), q[2].front());
    if (cur >= INT_MAX) break;
    ans = std::min<i64>(ans, cur + len);
  }
}

int main() {
  scanf("%d%d%d", &r, &c, &n);
  for (int i = 1; i <= n; ++i) scanf("%d%d", &p[i].x, &p[i].y);
  std::sort(p + 1, p + n + 1);
  std::vector<int> cur;
  for (int i = 1; i <= n; ++i) init(i);
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j < i; ++j)
      cur.push_back(std::max(p[i].x - p[j].x - 1, 0));
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= n; ++j)
      cur.push_back(p[i].x - 1 + r - p[j].x);
  for (int i = 1; i <= n; ++i) cur.push_back(p[i].x - 1), cur.push_back(r - p[i].x);
  cur.push_back(0);
  std::sort(cur.begin(), cur.end());
  cur.erase(std::unique(cur.begin(), cur.end()), cur.end());
  ans = INT_MAX;
  for (int i = 0; i < cur.size(); ++i) solve(cur[i]);
  printf("%d\n", ans);
  return 0;
}

Compilation message (stderr)

cultivation.cpp: In function 'int main()':
cultivation.cpp:102:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < cur.size(); ++i) solve(cur[i]);
                     ^
cultivation.cpp:86:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d", &r, &c, &n);
                              ^
cultivation.cpp:87:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   for (int i = 1; i <= n; ++i) scanf("%d%d", &p[i].x, &p[i].y);
                                                               ^

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 20 / 20
• Subtask 6: 20 / 20