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Submission #245319

# Submission time Handle Problem Language Result Execution time Memory
245319 2020-07-06T03:47:42 Z neihcr7j Boat (APIO16_boat) C++14
9 / 100
 621 ms 5052 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 (i == ret.size() || ret[i] != ret[i + 1]) {
        seg.push_back({ret[i - 1] + 1, ret[i]});
        continue;
      }

      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)));
    }

    int index = 0;

    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]);

      while (index < a[i].size() && a[i][index] <= k)
        index++;

      for (int j = index; j < a[i].size(); ++j)
        dp[i][a[i][j]] = norm(dp[i][a[i][j]] + mul(res, val[j - index + 1]));

      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:77:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if (i == ret.size() || ret[i] != ret[i + 1]) {
           ~~^~~~~~~~~~~~~
boat.cpp:90:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seg.size(); ++i) {
                   ~~^~~~~~~~~~~~
boat.cpp:99:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < seg.size(); ++i) {
                   ~~^~~~~~~~~~~~
boat.cpp:106:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int k = 1; k <= a[i].size(); ++k) {
                     ~~^~~~~~~~~~~~~~
boat.cpp:123:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       while (index < a[i].size() && a[i][index] <= k)
              ~~~~~~^~~~~~~~~~~~~
boat.cpp:126:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for (int j = index; j < a[i].size(); ++j)
                           ~~^~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 438 ms 2424 KB Output is correct
2 Correct 429 ms 2552 KB Output is correct
3 Correct 437 ms 2552 KB Output is correct
4 Correct 432 ms 2428 KB Output is correct
5 Correct 427 ms 2552 KB Output is correct
6 Correct 437 ms 2552 KB Output is correct
7 Correct 429 ms 2404 KB Output is correct
8 Correct 433 ms 2552 KB Output is correct
9 Correct 428 ms 2424 KB Output is correct
10 Correct 432 ms 2444 KB Output is correct
11 Correct 429 ms 2424 KB Output is correct
12 Correct 429 ms 2424 KB Output is correct
13 Correct 435 ms 2428 KB Output is correct
14 Correct 431 ms 2552 KB Output is correct
15 Correct 430 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 896 KB Output is correct
19 Correct 21 ms 1024 KB Output is correct
20 Correct 23 ms 896 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 438 ms 2424 KB Output is correct
2 Correct 429 ms 2552 KB Output is correct
3 Correct 437 ms 2552 KB Output is correct
4 Correct 432 ms 2428 KB Output is correct
5 Correct 427 ms 2552 KB Output is correct
6 Correct 437 ms 2552 KB Output is correct
7 Correct 429 ms 2404 KB Output is correct
8 Correct 433 ms 2552 KB Output is correct
9 Correct 428 ms 2424 KB Output is correct
10 Correct 432 ms 2444 KB Output is correct
11 Correct 429 ms 2424 KB Output is correct
12 Correct 429 ms 2424 KB Output is correct
13 Correct 435 ms 2428 KB Output is correct
14 Correct 431 ms 2552 KB Output is correct
15 Correct 430 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 896 KB Output is correct
19 Correct 21 ms 1024 KB Output is correct
20 Correct 23 ms 896 KB Output is correct
21 Incorrect 621 ms 5052 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 14 ms 1152 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 438 ms 2424 KB Output is correct
2 Correct 429 ms 2552 KB Output is correct
3 Correct 437 ms 2552 KB Output is correct
4 Correct 432 ms 2428 KB Output is correct
5 Correct 427 ms 2552 KB Output is correct
6 Correct 437 ms 2552 KB Output is correct
7 Correct 429 ms 2404 KB Output is correct
8 Correct 433 ms 2552 KB Output is correct
9 Correct 428 ms 2424 KB Output is correct
10 Correct 432 ms 2444 KB Output is correct
11 Correct 429 ms 2424 KB Output is correct
12 Correct 429 ms 2424 KB Output is correct
13 Correct 435 ms 2428 KB Output is correct
14 Correct 431 ms 2552 KB Output is correct
15 Correct 430 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 896 KB Output is correct
19 Correct 21 ms 1024 KB Output is correct
20 Correct 23 ms 896 KB Output is correct
21 Incorrect 621 ms 5052 KB Output isn't correct
22 Halted 0 ms 0 KB -