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Submission #245317

# Submission time Handle Problem Language Result Execution time Memory
245317 2020-07-06T03:27:17 Z neihcr7j Boat (APIO16_boat) C++14
36 / 100
 2000 ms 7916 KB 
#include<bits/stdc++.h>

#define M 1000000007
#define maxn 502

using namespace std;
typedef long long ll;

inline ll norm(ll a) {
  return (a < 0 ? a + M : (a >= M ? a - M : a));
}

inline ll mul(ll a, ll b) {
  return a * b % M;
}

ll power(ll a, ll b) {
  if (b == 0) return 1;
  if (b&1) return mul(power(a, b - 1), a);
  ll t = power(a, b / 2);
  return mul(t, t);
}

ll gt[maxn * 2], igt[maxn * 2];

void precalc(){
  int n = 1000;

  gt[0] = 1;
  for (int i = 1; i <= n; ++i)
    gt[i] = mul(gt[i - 1], i);

  igt[n] = power(gt[n], M - 2);

  for (int i = n - 1; i >= 0; --i)
    igt[i] = mul(igt[i + 1], i + 1);
}

ll C(int n, int k) {
  return mul(mul(gt[n], igt[k]), igt[n - k]);
}


int n;

int l[maxn], r[maxn];
vector < pair < int, int > > seg;
vector < vector < int > > a;
vector < int > leng;

ll dp[maxn * 4][maxn];

int main(){
  #define TASK "ABC"
 // freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout);
  ios_base::sync_with_stdio(0);

  precalc();

  cin >> n;

  vector < int > ret;

  for (int i = 1; i <= n; ++i) {
    cin >> l[i] >> r[i];

    ret.push_back(l[i]);
    ret.push_back(r[i]);
  }

  sort(ret.begin(), ret.end());

  seg.push_back({ret[0], ret[0]});

  for (int i = 1; i < ret.size(); ++i)
    if (ret[i] != ret[i - 1]) {
      if (ret[i - 1] + 1 != ret[i])
        seg.push_back({ret[i - 1] + 1, ret[i] - 1});
      seg.push_back({ret[i], ret[i]});
    }

  a = vector < vector < int > >(seg.size(), vector < int >(0, 0));
  leng = vector < int > (seg.size(), 0);

  for (int i = 0; i < seg.size(); ++i) {
    for (int j = 1; j <= n; ++j)
      if (l[j] <= seg[i].first && seg[i].second <= r[j])
        a[i].push_back(j);
    leng[i] = seg[i].second - seg[i].first + 1;
  }

  ll ans = 0;

  for (int i = 0; i < seg.size(); ++i) {
    ll l = leng[i];

    vector < ll > c(a[i].size() + 1, 0), val(a[i].size() + 1, 0);

    c[0] = 1;

    for (int k = 1; k <= a[i].size(); ++k) {
      if (k <= l)
        c[k] = mul(mul(c[k - 1], l - k + 1), power(k, M - 2));

      for (int x = k; x > 0; --x)
        if (x <= l)
          val[k] = norm(val[k] + mul(c[x], C(k - 1, x - 1)));
    }

    for (int k = 0; k <= n; ++k) {
      ll res = (k == 0 ? 1 : 0);

      for (int j = 0; j < i; ++j)
        res = norm(res + dp[j][k]);

      int cnt = 0;
      for (auto j : a[i])
        if (j > k) {
          cnt++;

          dp[i][j] = norm(dp[i][j] + mul(res, val[cnt]));
        }

      ans = norm(ans + dp[i][k]);
    }
  }

  cout << ans;

  return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:75:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 1; i < ret.size(); ++i)
                   ~~^~~~~~~~~~~~
boat.cpp:85:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seg.size(); ++i) {
                   ~~^~~~~~~~~~~~
boat.cpp:94:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seg.size(); ++i) {
                   ~~^~~~~~~~~~~~
boat.cpp:101:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int k = 1; k <= a[i].size(); ++k) {
                     ~~^~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 436 ms 2424 KB Output is correct
2 Correct 432 ms 2428 KB Output is correct
3 Correct 428 ms 2424 KB Output is correct
4 Correct 434 ms 2388 KB Output is correct
5 Correct 429 ms 2424 KB Output is correct
6 Correct 440 ms 2424 KB Output is correct
7 Correct 433 ms 2360 KB Output is correct
8 Correct 432 ms 2680 KB Output is correct
9 Correct 432 ms 2428 KB Output is correct
10 Correct 430 ms 2552 KB Output is correct
11 Correct 440 ms 2552 KB Output is correct
12 Correct 441 ms 2600 KB Output is correct
13 Correct 433 ms 2424 KB Output is correct
14 Correct 431 ms 2432 KB Output is correct
15 Correct 438 ms 2424 KB Output is correct
16 Correct 19 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 1024 KB Output is correct
19 Correct 21 ms 896 KB Output is correct
20 Correct 22 ms 932 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 436 ms 2424 KB Output is correct
2 Correct 432 ms 2428 KB Output is correct
3 Correct 428 ms 2424 KB Output is correct
4 Correct 434 ms 2388 KB Output is correct
5 Correct 429 ms 2424 KB Output is correct
6 Correct 440 ms 2424 KB Output is correct
7 Correct 433 ms 2360 KB Output is correct
8 Correct 432 ms 2680 KB Output is correct
9 Correct 432 ms 2428 KB Output is correct
10 Correct 430 ms 2552 KB Output is correct
11 Correct 440 ms 2552 KB Output is correct
12 Correct 441 ms 2600 KB Output is correct
13 Correct 433 ms 2424 KB Output is correct
14 Correct 431 ms 2432 KB Output is correct
15 Correct 438 ms 2424 KB Output is correct
16 Correct 19 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 1024 KB Output is correct
19 Correct 21 ms 896 KB Output is correct
20 Correct 22 ms 932 KB Output is correct
21 Execution timed out 2081 ms 7916 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 2048 KB Output is correct
2 Correct 25 ms 2040 KB Output is correct
3 Correct 26 ms 2040 KB Output is correct
4 Correct 26 ms 2048 KB Output is correct
5 Correct 27 ms 2048 KB Output is correct
6 Correct 31 ms 2040 KB Output is correct
7 Correct 36 ms 2040 KB Output is correct
8 Correct 32 ms 2048 KB Output is correct
9 Correct 30 ms 2048 KB Output is correct
10 Correct 30 ms 2048 KB Output is correct
11 Correct 27 ms 2048 KB Output is correct
12 Correct 26 ms 2040 KB Output is correct
13 Correct 26 ms 2048 KB Output is correct
14 Correct 26 ms 2048 KB Output is correct
15 Correct 27 ms 2048 KB Output is correct
16 Correct 10 ms 1024 KB Output is correct
17 Correct 11 ms 1152 KB Output is correct
18 Correct 11 ms 1024 KB Output is correct
19 Correct 11 ms 1024 KB Output is correct
20 Correct 11 ms 1152 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 436 ms 2424 KB Output is correct
2 Correct 432 ms 2428 KB Output is correct
3 Correct 428 ms 2424 KB Output is correct
4 Correct 434 ms 2388 KB Output is correct
5 Correct 429 ms 2424 KB Output is correct
6 Correct 440 ms 2424 KB Output is correct
7 Correct 433 ms 2360 KB Output is correct
8 Correct 432 ms 2680 KB Output is correct
9 Correct 432 ms 2428 KB Output is correct
10 Correct 430 ms 2552 KB Output is correct
11 Correct 440 ms 2552 KB Output is correct
12 Correct 441 ms 2600 KB Output is correct
13 Correct 433 ms 2424 KB Output is correct
14 Correct 431 ms 2432 KB Output is correct
15 Correct 438 ms 2424 KB Output is correct
16 Correct 19 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 1024 KB Output is correct
19 Correct 21 ms 896 KB Output is correct
20 Correct 22 ms 932 KB Output is correct
21 Execution timed out 2081 ms 7916 KB Time limit exceeded
22 Halted 0 ms 0 KB -