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Submission #245313

# Submission time Handle Problem Language Result Execution time Memory
245313 2020-07-06T03:15:11 Z neihcr7j Boat (APIO16_boat) C++14
36 / 100
 2000 ms 15932 KB 
#include<bits/stdc++.h>

#define M 1000000007
#define maxn 502

using namespace std;
typedef long long ll;

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

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], igt[maxn];

void precalc(){
  int n = 500;

  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 * 3][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 427 ms 2424 KB Output is correct
2 Correct 434 ms 2552 KB Output is correct
3 Correct 439 ms 2424 KB Output is correct
4 Correct 439 ms 2360 KB Output is correct
5 Correct 436 ms 2424 KB Output is correct
6 Correct 433 ms 2552 KB Output is correct
7 Correct 429 ms 2552 KB Output is correct
8 Correct 428 ms 2468 KB Output is correct
9 Correct 429 ms 2424 KB Output is correct
10 Correct 429 ms 2424 KB Output is correct
11 Correct 430 ms 2424 KB Output is correct
12 Correct 442 ms 2424 KB Output is correct
13 Correct 438 ms 2412 KB Output is correct
14 Correct 429 ms 2552 KB Output is correct
15 Correct 434 ms 2412 KB Output is correct
16 Correct 20 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 896 KB Output is correct
19 Correct 22 ms 896 KB Output is correct
20 Correct 20 ms 1024 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 427 ms 2424 KB Output is correct
2 Correct 434 ms 2552 KB Output is correct
3 Correct 439 ms 2424 KB Output is correct
4 Correct 439 ms 2360 KB Output is correct
5 Correct 436 ms 2424 KB Output is correct
6 Correct 433 ms 2552 KB Output is correct
7 Correct 429 ms 2552 KB Output is correct
8 Correct 428 ms 2468 KB Output is correct
9 Correct 429 ms 2424 KB Output is correct
10 Correct 429 ms 2424 KB Output is correct
11 Correct 430 ms 2424 KB Output is correct
12 Correct 442 ms 2424 KB Output is correct
13 Correct 438 ms 2412 KB Output is correct
14 Correct 429 ms 2552 KB Output is correct
15 Correct 434 ms 2412 KB Output is correct
16 Correct 20 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 896 KB Output is correct
19 Correct 22 ms 896 KB Output is correct
20 Correct 20 ms 1024 KB Output is correct
21 Execution timed out 2047 ms 15932 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 2048 KB Output is correct
2 Correct 26 ms 2048 KB Output is correct
3 Correct 29 ms 2040 KB Output is correct
4 Correct 26 ms 2048 KB Output is correct
5 Correct 29 ms 2048 KB Output is correct
6 Correct 31 ms 2040 KB Output is correct
7 Correct 33 ms 2048 KB Output is correct
8 Correct 31 ms 2060 KB Output is correct
9 Correct 31 ms 2040 KB Output is correct
10 Correct 31 ms 2068 KB Output is correct
11 Correct 28 ms 2040 KB Output is correct
12 Correct 25 ms 2048 KB Output is correct
13 Correct 26 ms 2040 KB Output is correct
14 Correct 26 ms 2040 KB Output is correct
15 Correct 27 ms 2048 KB Output is correct
16 Correct 11 ms 1024 KB Output is correct
17 Correct 11 ms 1024 KB Output is correct
18 Correct 11 ms 1024 KB Output is correct
19 Correct 11 ms 1024 KB Output is correct
20 Correct 12 ms 1152 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 427 ms 2424 KB Output is correct
2 Correct 434 ms 2552 KB Output is correct
3 Correct 439 ms 2424 KB Output is correct
4 Correct 439 ms 2360 KB Output is correct
5 Correct 436 ms 2424 KB Output is correct
6 Correct 433 ms 2552 KB Output is correct
7 Correct 429 ms 2552 KB Output is correct
8 Correct 428 ms 2468 KB Output is correct
9 Correct 429 ms 2424 KB Output is correct
10 Correct 429 ms 2424 KB Output is correct
11 Correct 430 ms 2424 KB Output is correct
12 Correct 442 ms 2424 KB Output is correct
13 Correct 438 ms 2412 KB Output is correct
14 Correct 429 ms 2552 KB Output is correct
15 Correct 434 ms 2412 KB Output is correct
16 Correct 20 ms 896 KB Output is correct
17 Correct 21 ms 896 KB Output is correct
18 Correct 20 ms 896 KB Output is correct
19 Correct 22 ms 896 KB Output is correct
20 Correct 20 ms 1024 KB Output is correct
21 Execution timed out 2047 ms 15932 KB Time limit exceeded
22 Halted 0 ms 0 KB -