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Submission #245310

# Submission time Handle Problem Language Result Execution time Memory
245310 2020-07-06T02:56:47 Z neihcr7j Boat (APIO16_boat) C++14
9 / 100
 2000 ms 6116 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(int a, int b) {
  if (b == 0) return 1;
  if (b&1) return mul(power(a, b - 1), a);
  int 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 222 ms 2420 KB Output is correct
2 Correct 228 ms 2552 KB Output is correct
3 Correct 229 ms 2448 KB Output is correct
4 Correct 229 ms 2396 KB Output is correct
5 Correct 231 ms 2424 KB Output is correct
6 Correct 228 ms 2528 KB Output is correct
7 Correct 234 ms 2440 KB Output is correct
8 Correct 229 ms 2372 KB Output is correct
9 Correct 233 ms 2472 KB Output is correct
10 Correct 225 ms 2388 KB Output is correct
11 Correct 285 ms 2424 KB Output is correct
12 Correct 225 ms 2532 KB Output is correct
13 Correct 236 ms 2552 KB Output is correct
14 Correct 220 ms 2424 KB Output is correct
15 Correct 229 ms 2468 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 1024 KB Output is correct
20 Correct 13 ms 1024 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 222 ms 2420 KB Output is correct
2 Correct 228 ms 2552 KB Output is correct
3 Correct 229 ms 2448 KB Output is correct
4 Correct 229 ms 2396 KB Output is correct
5 Correct 231 ms 2424 KB Output is correct
6 Correct 228 ms 2528 KB Output is correct
7 Correct 234 ms 2440 KB Output is correct
8 Correct 229 ms 2372 KB Output is correct
9 Correct 233 ms 2472 KB Output is correct
10 Correct 225 ms 2388 KB Output is correct
11 Correct 285 ms 2424 KB Output is correct
12 Correct 225 ms 2532 KB Output is correct
13 Correct 236 ms 2552 KB Output is correct
14 Correct 220 ms 2424 KB Output is correct
15 Correct 229 ms 2468 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 1024 KB Output is correct
20 Correct 13 ms 1024 KB Output is correct
21 Execution timed out 2084 ms 6116 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 324 ms 2168 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 222 ms 2420 KB Output is correct
2 Correct 228 ms 2552 KB Output is correct
3 Correct 229 ms 2448 KB Output is correct
4 Correct 229 ms 2396 KB Output is correct
5 Correct 231 ms 2424 KB Output is correct
6 Correct 228 ms 2528 KB Output is correct
7 Correct 234 ms 2440 KB Output is correct
8 Correct 229 ms 2372 KB Output is correct
9 Correct 233 ms 2472 KB Output is correct
10 Correct 225 ms 2388 KB Output is correct
11 Correct 285 ms 2424 KB Output is correct
12 Correct 225 ms 2532 KB Output is correct
13 Correct 236 ms 2552 KB Output is correct
14 Correct 220 ms 2424 KB Output is correct
15 Correct 229 ms 2468 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 1024 KB Output is correct
20 Correct 13 ms 1024 KB Output is correct
21 Execution timed out 2084 ms 6116 KB Time limit exceeded
22 Halted 0 ms 0 KB -