oj.uz

Submission #23488

# Submission time Handle Problem Language Result Execution time Memory
23488 2017-05-10T11:35:03 Z Nirjhor Boat (APIO16_boat) C++14
36 / 100
 2000 ms 11204 KB 
#include <bits/stdc++.h> 

using namespace std;

typedef long long ll;
typedef pair <ll, ll> pii;

const int N = 505;
const int M = 1005;
const int MOD = 1e9 + 7;

int n, m;
ll a[N], b[N];
ll dp[N][M];
vector <pii> v;
ll x[M], y[M];
vector <int> z[M];
int sz[M];
ll wide[M];
int counter = 1;
ll comb[M][N];
ll inverse[N];

ll bigMod (ll a, ll e) {
  if (e == -1) e = MOD - 2;
  ll r = 1ll; while (e) {
    if (e & 1) r = (r * a) % MOD;
    a = (a * a) % MOD;
    e >>= 1;
  }
  return r;
}

ll call (int at, int range) {
  if (at > n or range > m) return 1;
  if (dp[at][range] != -1) return dp[at][range];
  int pos = 0;
  while (pos < sz[range] and z[range][pos] < at) {
    ++pos;
  }
  ll ret = call(at, range + 1);
  for (int i = pos; i < sz[range]; ++i) {
    int rem = i - pos, cur = z[range][i];
    // cout << rem << " comb ---> " << comb[range][rem] << endl;
    ll add = (comb[range][rem] * call(cur + 1, range + 1)) % MOD;
    ret += add, ret %= MOD;
  }
  return dp[at][range] = ret;
}

ll nCr (ll n, ll r) {
  if (n < r or n < 0 or r < 0) return 0;
  ll res = 1ll;
  for (ll i = n; i >= n - r + 1; --i) {
    res *= i, res %= MOD;
  }
  for (ll i = 1; i <= r; ++i) {
    res *= inverse[i];
    res %= MOD;
  }
  return res;
}

int main (int argc, char const *argv[]) {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%lld %lld", a + i, b + i);
    v.push_back({a[i], 0});
    v.push_back({b[i], 1});
  }
  sort(v.begin(), v.end());
  for (int i = 1; i < n + n; ++i) {
    int one = v[i - 1].second, two = v[i].second;
    int l = v[i - 1].first, r = v[i].first;
    if (!one and !two) {
      --r, ++counter;
      if (l <= r) x[++m] = l, y[m] = r;
    } else if (!one and two) {
      --counter;
      // cout << "yo " << i << " " << m << endl;
      if (l <= r) x[++m] = l, y[m] = r;
    } else if (one and two) {
      ++l, --counter;
      if (l <= r) x[++m] = l, y[m] = r; 
    } else {
      ++l, --r;
      if (counter and l <= r) x[++m] = l, y[m] = r;
      ++counter;
    }
  }
  // cout << m << endl;
  // for (int i = 1; i <= m; ++i) {
  //   cout << x[i] << " " << y[i] << endl;
  // }
  for (int i = 1; i <= m; ++i) {
    for (int j = 1; j <= n; ++j) {
      if (a[j] <= x[i] and y[i] <= b[j]) {
        z[i].push_back(j);
        ++sz[i];
      }
    }
    wide[i] = y[i] - x[i] + 1;
  } 
  for (int i = 1; i < N; ++i) {
    inverse[i] = bigMod(i, -1);
  }
  for (int i = 1; i <= m; ++i) {
    for (int j = 0; j <= n; ++j) {
      comb[i][j] = nCr(wide[i] + j, j + 1);
    }
  }
  // for (int i = 1; i <= m; ++i) {
  //   cout << i << " --> ";
  //   for (int j : z[i]) cout << j << " ";
  //   cout << endl;
  // } 
  memset(dp, -1, sizeof dp);
  // for (int i = 1; i <= n; ++i) {
  //   for (int j = 1; j <= m; ++j) {
  //     cout << "(" << i << ", " << j << ") ---> " << call(i, j) << endl;
  //   }
  // }
  ll ans = call(1, 1) + MOD - 1;
  printf("%lld\n", ans % MOD);
  return 0;
}

Compilation message

boat.cpp: In function 'int main(int, const char**)':
boat.cpp:65:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
                  ^
boat.cpp:67:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld %lld", a + i, b + i);
                                     ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 786 ms 10016 KB Output is correct
2 Correct 786 ms 10016 KB Output is correct
3 Correct 789 ms 10016 KB Output is correct
4 Correct 786 ms 10016 KB Output is correct
5 Correct 783 ms 10016 KB Output is correct
6 Correct 783 ms 10016 KB Output is correct
7 Correct 803 ms 10016 KB Output is correct
8 Correct 783 ms 10016 KB Output is correct
9 Correct 783 ms 10016 KB Output is correct
10 Correct 783 ms 10016 KB Output is correct
11 Correct 783 ms 10016 KB Output is correct
12 Correct 786 ms 10016 KB Output is correct
13 Correct 779 ms 10016 KB Output is correct
14 Correct 786 ms 10016 KB Output is correct
15 Correct 779 ms 10016 KB Output is correct
16 Correct 139 ms 10016 KB Output is correct
17 Correct 146 ms 10016 KB Output is correct
18 Correct 146 ms 10016 KB Output is correct
19 Correct 153 ms 10016 KB Output is correct
20 Correct 146 ms 10016 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 786 ms 10016 KB Output is correct
2 Correct 786 ms 10016 KB Output is correct
3 Correct 789 ms 10016 KB Output is correct
4 Correct 786 ms 10016 KB Output is correct
5 Correct 783 ms 10016 KB Output is correct
6 Correct 783 ms 10016 KB Output is correct
7 Correct 803 ms 10016 KB Output is correct
8 Correct 783 ms 10016 KB Output is correct
9 Correct 783 ms 10016 KB Output is correct
10 Correct 783 ms 10016 KB Output is correct
11 Correct 783 ms 10016 KB Output is correct
12 Correct 786 ms 10016 KB Output is correct
13 Correct 779 ms 10016 KB Output is correct
14 Correct 786 ms 10016 KB Output is correct
15 Correct 779 ms 10016 KB Output is correct
16 Correct 139 ms 10016 KB Output is correct
17 Correct 146 ms 10016 KB Output is correct
18 Correct 146 ms 10016 KB Output is correct
19 Correct 153 ms 10016 KB Output is correct
20 Correct 146 ms 10016 KB Output is correct
21 Correct 1816 ms 10808 KB Output is correct
22 Correct 1759 ms 10940 KB Output is correct
23 Correct 1709 ms 10808 KB Output is correct
24 Correct 1743 ms 10808 KB Output is correct
25 Correct 1769 ms 10808 KB Output is correct
26 Execution timed out 2000 ms 11204 KB Execution timed out
27 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 10016 KB Output is correct
2 Correct 13 ms 10016 KB Output is correct
3 Correct 13 ms 10016 KB Output is correct
4 Correct 16 ms 10016 KB Output is correct
5 Correct 16 ms 10016 KB Output is correct
6 Correct 16 ms 10148 KB Output is correct
7 Correct 13 ms 10148 KB Output is correct
8 Correct 23 ms 10148 KB Output is correct
9 Correct 16 ms 10148 KB Output is correct
10 Correct 16 ms 10148 KB Output is correct
11 Correct 19 ms 10016 KB Output is correct
12 Correct 19 ms 10016 KB Output is correct
13 Correct 16 ms 10016 KB Output is correct
14 Correct 19 ms 10016 KB Output is correct
15 Correct 16 ms 10016 KB Output is correct
16 Correct 6 ms 10016 KB Output is correct
17 Correct 6 ms 10016 KB Output is correct
18 Correct 13 ms 10016 KB Output is correct
19 Correct 9 ms 10016 KB Output is correct
20 Correct 9 ms 10016 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 786 ms 10016 KB Output is correct
2 Correct 786 ms 10016 KB Output is correct
3 Correct 789 ms 10016 KB Output is correct
4 Correct 786 ms 10016 KB Output is correct
5 Correct 783 ms 10016 KB Output is correct
6 Correct 783 ms 10016 KB Output is correct
7 Correct 803 ms 10016 KB Output is correct
8 Correct 783 ms 10016 KB Output is correct
9 Correct 783 ms 10016 KB Output is correct
10 Correct 783 ms 10016 KB Output is correct
11 Correct 783 ms 10016 KB Output is correct
12 Correct 786 ms 10016 KB Output is correct
13 Correct 779 ms 10016 KB Output is correct
14 Correct 786 ms 10016 KB Output is correct
15 Correct 779 ms 10016 KB Output is correct
16 Correct 139 ms 10016 KB Output is correct
17 Correct 146 ms 10016 KB Output is correct
18 Correct 146 ms 10016 KB Output is correct
19 Correct 153 ms 10016 KB Output is correct
20 Correct 146 ms 10016 KB Output is correct
21 Correct 1816 ms 10808 KB Output is correct
22 Correct 1759 ms 10940 KB Output is correct
23 Correct 1709 ms 10808 KB Output is correct
24 Correct 1743 ms 10808 KB Output is correct
25 Correct 1769 ms 10808 KB Output is correct
26 Execution timed out 2000 ms 11204 KB Execution timed out
27 Halted 0 ms 0 KB -