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Submission #23492

# Submission time Handle Problem Language Result Execution time Memory
23492 2017-05-10T12:04:22 Z Nirjhor Boat (APIO16_boat) C++14
100 / 100
 989 ms 9336 KB 
#include <bits/stdc++.h> 

using namespace std;

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

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

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

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

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

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

int main (int argc, char const *argv[]) {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d %d", 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;
      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;
    }
  }
  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 <= sz[i]; ++j) {
      comb[i][j] = nCr(wide[i] + j, j + 1);
    }
  }
  for (int i = 0; i <= n + 1; ++i) {
    dp[i][m + 1] = 1;
  }
  for (int i = 0; i <= m + 1; ++i) {
    dp[n + 1][i] = 1;
  }
  for (int at = n; at; --at) {
    for (int range = m; range; --range) {
      dp[at][range] = dp[at][range + 1];
      int start = 0;
      while (start < sz[range] and z[range][start] < at) ++start;
      for (int i = start; i < sz[range]; ++i) {
        dp[at][range] += comb[range][i - start] * dp[z[range][i] + 1][range + 1];
        dp[at][range] %= MOD;
      }
    }
  }
  // for (int i = 1; i <= n; ++i) {
  //   for (int j = 1; j <= m; ++j) {
  //     cout << "(" << i << ", " << j << ") ---> " << dp[i][j] << endl;
  //   }
  // }
  dp[1][1] += MOD - 1, dp[1][1] %= MOD;
  printf("%lld\n", dp[1][1]);
  return 0;
}

Compilation message

boat.cpp: In function 'int main(int, const char**)':
boat.cpp:55:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
                  ^
boat.cpp:57:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", a + i, b + i);
                                 ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 6 ms 8016 KB Output is correct
3 Correct 3 ms 8016 KB Output is correct
4 Correct 0 ms 8016 KB Output is correct
5 Correct 6 ms 8016 KB Output is correct
6 Correct 0 ms 8016 KB Output is correct
7 Correct 0 ms 8016 KB Output is correct
8 Correct 6 ms 8016 KB Output is correct
9 Correct 0 ms 8016 KB Output is correct
10 Correct 3 ms 8016 KB Output is correct
11 Correct 3 ms 8016 KB Output is correct
12 Correct 3 ms 8016 KB Output is correct
13 Correct 0 ms 8016 KB Output is correct
14 Correct 0 ms 8016 KB Output is correct
15 Correct 0 ms 8016 KB Output is correct
16 Correct 0 ms 8016 KB Output is correct
17 Correct 3 ms 8016 KB Output is correct
18 Correct 0 ms 8016 KB Output is correct
19 Correct 3 ms 8016 KB Output is correct
20 Correct 3 ms 8016 KB Output is correct

Subtask #2
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 6 ms 8016 KB Output is correct
3 Correct 3 ms 8016 KB Output is correct
4 Correct 0 ms 8016 KB Output is correct
5 Correct 6 ms 8016 KB Output is correct
6 Correct 0 ms 8016 KB Output is correct
7 Correct 0 ms 8016 KB Output is correct
8 Correct 6 ms 8016 KB Output is correct
9 Correct 0 ms 8016 KB Output is correct
10 Correct 3 ms 8016 KB Output is correct
11 Correct 3 ms 8016 KB Output is correct
12 Correct 3 ms 8016 KB Output is correct
13 Correct 0 ms 8016 KB Output is correct
14 Correct 0 ms 8016 KB Output is correct
15 Correct 0 ms 8016 KB Output is correct
16 Correct 0 ms 8016 KB Output is correct
17 Correct 3 ms 8016 KB Output is correct
18 Correct 0 ms 8016 KB Output is correct
19 Correct 3 ms 8016 KB Output is correct
20 Correct 3 ms 8016 KB Output is correct
21 Correct 516 ms 8808 KB Output is correct
22 Correct 503 ms 8940 KB Output is correct
23 Correct 466 ms 8808 KB Output is correct
24 Correct 483 ms 8808 KB Output is correct
25 Correct 466 ms 8808 KB Output is correct
26 Correct 866 ms 9204 KB Output is correct
27 Correct 903 ms 9204 KB Output is correct
28 Correct 893 ms 9204 KB Output is correct
29 Correct 863 ms 9204 KB Output is correct
30 Correct 9 ms 8016 KB Output is correct
31 Correct 3 ms 8016 KB Output is correct
32 Correct 9 ms 8016 KB Output is correct
33 Correct 6 ms 8016 KB Output is correct
34 Correct 3 ms 8016 KB Output is correct
35 Correct 6 ms 8016 KB Output is correct
36 Correct 6 ms 8016 KB Output is correct
37 Correct 9 ms 8016 KB Output is correct
38 Correct 9 ms 8016 KB Output is correct

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 3 ms 8016 KB Output is correct
3 Correct 3 ms 8016 KB Output is correct
4 Correct 0 ms 8016 KB Output is correct
5 Correct 6 ms 8016 KB Output is correct
6 Correct 6 ms 8148 KB Output is correct
7 Correct 6 ms 8148 KB Output is correct
8 Correct 6 ms 8148 KB Output is correct
9 Correct 6 ms 8148 KB Output is correct
10 Correct 6 ms 8148 KB Output is correct
11 Correct 3 ms 8016 KB Output is correct
12 Correct 3 ms 8016 KB Output is correct
13 Correct 3 ms 8016 KB Output is correct
14 Correct 3 ms 8016 KB Output is correct
15 Correct 3 ms 8016 KB Output is correct
16 Correct 3 ms 8016 KB Output is correct
17 Correct 0 ms 8016 KB Output is correct
18 Correct 0 ms 8016 KB Output is correct
19 Correct 3 ms 8016 KB Output is correct
20 Correct 3 ms 8016 KB Output is correct

Subtask #4
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 6 ms 8016 KB Output is correct
3 Correct 3 ms 8016 KB Output is correct
4 Correct 0 ms 8016 KB Output is correct
5 Correct 6 ms 8016 KB Output is correct
6 Correct 0 ms 8016 KB Output is correct
7 Correct 0 ms 8016 KB Output is correct
8 Correct 6 ms 8016 KB Output is correct
9 Correct 0 ms 8016 KB Output is correct
10 Correct 3 ms 8016 KB Output is correct
11 Correct 3 ms 8016 KB Output is correct
12 Correct 3 ms 8016 KB Output is correct
13 Correct 0 ms 8016 KB Output is correct
14 Correct 0 ms 8016 KB Output is correct
15 Correct 0 ms 8016 KB Output is correct
16 Correct 0 ms 8016 KB Output is correct
17 Correct 3 ms 8016 KB Output is correct
18 Correct 0 ms 8016 KB Output is correct
19 Correct 3 ms 8016 KB Output is correct
20 Correct 3 ms 8016 KB Output is correct
21 Correct 516 ms 8808 KB Output is correct
22 Correct 503 ms 8940 KB Output is correct
23 Correct 466 ms 8808 KB Output is correct
24 Correct 483 ms 8808 KB Output is correct
25 Correct 466 ms 8808 KB Output is correct
26 Correct 866 ms 9204 KB Output is correct
27 Correct 903 ms 9204 KB Output is correct
28 Correct 893 ms 9204 KB Output is correct
29 Correct 863 ms 9204 KB Output is correct
30 Correct 9 ms 8016 KB Output is correct
31 Correct 3 ms 8016 KB Output is correct
32 Correct 9 ms 8016 KB Output is correct
33 Correct 6 ms 8016 KB Output is correct
34 Correct 3 ms 8016 KB Output is correct
35 Correct 6 ms 8016 KB Output is correct
36 Correct 6 ms 8016 KB Output is correct
37 Correct 9 ms 8016 KB Output is correct
38 Correct 9 ms 8016 KB Output is correct
39 Correct 3 ms 8016 KB Output is correct
40 Correct 3 ms 8016 KB Output is correct
41 Correct 3 ms 8016 KB Output is correct
42 Correct 0 ms 8016 KB Output is correct
43 Correct 6 ms 8016 KB Output is correct
44 Correct 6 ms 8148 KB Output is correct
45 Correct 6 ms 8148 KB Output is correct
46 Correct 6 ms 8148 KB Output is correct
47 Correct 6 ms 8148 KB Output is correct
48 Correct 6 ms 8148 KB Output is correct
49 Correct 3 ms 8016 KB Output is correct
50 Correct 3 ms 8016 KB Output is correct
51 Correct 3 ms 8016 KB Output is correct
52 Correct 3 ms 8016 KB Output is correct
53 Correct 3 ms 8016 KB Output is correct
54 Correct 3 ms 8016 KB Output is correct
55 Correct 0 ms 8016 KB Output is correct
56 Correct 0 ms 8016 KB Output is correct
57 Correct 3 ms 8016 KB Output is correct
58 Correct 3 ms 8016 KB Output is correct
59 Correct 543 ms 8940 KB Output is correct
60 Correct 483 ms 8808 KB Output is correct
61 Correct 496 ms 8808 KB Output is correct
62 Correct 566 ms 9072 KB Output is correct
63 Correct 496 ms 8808 KB Output is correct
64 Correct 969 ms 9336 KB Output is correct
65 Correct 989 ms 9336 KB Output is correct
66 Correct 976 ms 9336 KB Output is correct
67 Correct 976 ms 9336 KB Output is correct
68 Correct 959 ms 9336 KB Output is correct
69 Correct 439 ms 8808 KB Output is correct
70 Correct 439 ms 8808 KB Output is correct
71 Correct 416 ms 8808 KB Output is correct
72 Correct 459 ms 8808 KB Output is correct
73 Correct 479 ms 8808 KB Output is correct
74 Correct 109 ms 8148 KB Output is correct
75 Correct 99 ms 8148 KB Output is correct
76 Correct 106 ms 8148 KB Output is correct
77 Correct 103 ms 8148 KB Output is correct
78 Correct 113 ms 8280 KB Output is correct