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Submission #245312

# Submission time Handle Problem Language Result Execution time Memory
245312 2020-07-06T03:07:13 Z neihcr7j Boat (APIO16_boat) C++14
9 / 100
 2000 ms 5956 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 = 1; k <= a[i].size() && k <= l; ++k)

    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) {
                     ~~^~~~~~~~~~~~~~
boat.cpp:110:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int k = 1; k <= a[i].size() && k <= l; ++k)
                     ~~^~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 217 ms 2424 KB Output is correct
2 Correct 238 ms 2424 KB Output is correct
3 Correct 230 ms 2552 KB Output is correct
4 Correct 225 ms 2424 KB Output is correct
5 Correct 225 ms 2424 KB Output is correct
6 Correct 220 ms 2424 KB Output is correct
7 Correct 219 ms 2424 KB Output is correct
8 Correct 223 ms 2424 KB Output is correct
9 Correct 220 ms 2552 KB Output is correct
10 Correct 217 ms 2424 KB Output is correct
11 Correct 218 ms 2424 KB Output is correct
12 Correct 217 ms 2408 KB Output is correct
13 Correct 218 ms 2424 KB Output is correct
14 Correct 219 ms 2424 KB Output is correct
15 Correct 218 ms 2424 KB Output is correct
16 Correct 13 ms 896 KB Output is correct
17 Correct 14 ms 896 KB Output is correct
18 Correct 13 ms 896 KB Output is correct
19 Correct 14 ms 896 KB Output is correct
20 Correct 13 ms 896 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 217 ms 2424 KB Output is correct
2 Correct 238 ms 2424 KB Output is correct
3 Correct 230 ms 2552 KB Output is correct
4 Correct 225 ms 2424 KB Output is correct
5 Correct 225 ms 2424 KB Output is correct
6 Correct 220 ms 2424 KB Output is correct
7 Correct 219 ms 2424 KB Output is correct
8 Correct 223 ms 2424 KB Output is correct
9 Correct 220 ms 2552 KB Output is correct
10 Correct 217 ms 2424 KB Output is correct
11 Correct 218 ms 2424 KB Output is correct
12 Correct 217 ms 2408 KB Output is correct
13 Correct 218 ms 2424 KB Output is correct
14 Correct 219 ms 2424 KB Output is correct
15 Correct 218 ms 2424 KB Output is correct
16 Correct 13 ms 896 KB Output is correct
17 Correct 14 ms 896 KB Output is correct
18 Correct 13 ms 896 KB Output is correct
19 Correct 14 ms 896 KB Output is correct
20 Correct 13 ms 896 KB Output is correct
21 Execution timed out 2090 ms 5956 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 330 ms 2040 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 217 ms 2424 KB Output is correct
2 Correct 238 ms 2424 KB Output is correct
3 Correct 230 ms 2552 KB Output is correct
4 Correct 225 ms 2424 KB Output is correct
5 Correct 225 ms 2424 KB Output is correct
6 Correct 220 ms 2424 KB Output is correct
7 Correct 219 ms 2424 KB Output is correct
8 Correct 223 ms 2424 KB Output is correct
9 Correct 220 ms 2552 KB Output is correct
10 Correct 217 ms 2424 KB Output is correct
11 Correct 218 ms 2424 KB Output is correct
12 Correct 217 ms 2408 KB Output is correct
13 Correct 218 ms 2424 KB Output is correct
14 Correct 219 ms 2424 KB Output is correct
15 Correct 218 ms 2424 KB Output is correct
16 Correct 13 ms 896 KB Output is correct
17 Correct 14 ms 896 KB Output is correct
18 Correct 13 ms 896 KB Output is correct
19 Correct 14 ms 896 KB Output is correct
20 Correct 13 ms 896 KB Output is correct
21 Execution timed out 2090 ms 5956 KB Time limit exceeded
22 Halted 0 ms 0 KB -