oj.uz

Submission #498606

# Submission time Handle Problem Language Result Execution time Memory
498606 2021-12-25T18:07:58 Z 600Mihnea Skyscraper (JOI16_skyscraper) C++17
100 / 100
 328 ms 3500 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int M = (int) 1e9 + 7;

int add(int a, int b) {
  a += b;
  if (a >= M) return a - M;
  if (a < 0) return a + M;
  return a;
}

int mul(int a, int b) {
  return a * (ll) b % M;
}

void addup(int &a, int b) {
  a = add(a, b);
}

void mulup(int &a, int b) {
  a = mul(a, b);
}

const int N = 100 + 7;
const int Z = 1000 + 7;
int n;
int limit;
int a[N];
int dp[N][Z][2][2]; /// ways[islands][sum]
int nwdp[N][Z][2][2];

void rst() {
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j < Z; j++) {
      for (int bg = 0; bg < 2; bg++) {
        for (int nd = 0; nd < 2; nd++) {
          dp[i][j][bg][nd] = nwdp[i][j][bg][nd];
          nwdp[i][j][bg][nd] = 0;
        }
      }
    }
  }
}

void addTo(int islands, int real_sum, int bg, int nd, int value) {
  assert(real_sum >= 0);
  if (islands >= 1 && real_sum < Z) {
    addup(nwdp[islands][real_sum][bg][nd], value);
  }
}

int main() {
  bool isHome;

  isHome = true;
  isHome = false;

  if (isHome) {
    freopen ("input", "r", stdin);
  } else {
    ios::sync_with_stdio(0); cin.tie(0);
  }


  cin >> n >> limit;


  if (n == 1) {
    cout << "1\n";
    return 0;
  }

  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  sort(a + 1, a + n + 1);

  /// it is the first

  dp[1][0][1][0] = 1;

  /// it is the last


  dp[1][0][0][1] = 1;

  /// it is in the middle


  dp[1][0][0][0] = 1;

  for (int it = 2; it <= n; it++) {
    int dif = a[it] - a[it - 1];
    for (int islands = 1; islands < it; islands++) {
      for (int sum = 0; sum < Z; sum++) {
        for (int bg = 0; bg < 2; bg++) {
          for (int nd = 0; nd < 2; nd++) {
            int dp_value = dp[islands][sum][bg][nd];
            if (dp_value == 0) {
              continue;
            }

            { /// create a new island

              /// make it the first

              if (bg == 0) {
                addTo(islands + 1, sum + dif * (2 * islands - bg - nd), 1, nd, dp_value);
              }

              /// make it the last

              if (nd == 0) {
                addTo(islands + 1, sum + dif * (2 * islands - bg - nd), bg, 1, dp_value);
              }

              /// place it in the middle

              int total_ways = (islands + 1) - bg - nd;

              addTo(islands + 1, sum + dif * (2 * islands - bg - nd), bg, nd, mul(dp_value, total_ways));

            }

            { /// put it next to some guy


              /// make it the first

              if (bg == 0) {
                addTo(islands, sum + dif * (2 * islands - bg - nd), 1, nd, dp_value);
              }

              /// make it the last

              if (nd == 0) {
                addTo(islands, sum + dif * (2 * islands - bg - nd), bg, 1, dp_value);
              }


              /// place it in the middle

              int total_ways = 2 * islands - bg - nd;

              addTo(islands, sum + dif * (2 * islands - bg - nd), bg, nd, mul(dp_value, total_ways));

            }

            if (islands >= 2) { /// join some guys

              int total_ways = (islands - 1);

              addTo(islands - 1, sum + dif * (2 * islands - bg - nd), bg, nd, mul(dp_value, total_ways));
            }

          }
        }
      }
    }
    rst();
  }

  int sol = 0;

  for (int sum = 0; sum <= limit; sum++) {
    int dp_value = dp[1][sum][1][1];

    if (dp_value) {
      addup(sol, dp_value);
    }
  }

  cout << sol << "\n";


  return 0;
}

Compilation message

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:63:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     freopen ("input", "r", stdin);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 588 KB Output is correct
6 Correct 1 ms 588 KB Output is correct
7 Correct 1 ms 588 KB Output is correct
8 Correct 1 ms 588 KB Output is correct
9 Correct 1 ms 588 KB Output is correct
10 Correct 1 ms 588 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 716 KB Output is correct
2 Correct 5 ms 716 KB Output is correct
3 Correct 3 ms 716 KB Output is correct
4 Correct 4 ms 716 KB Output is correct
5 Correct 4 ms 716 KB Output is correct
6 Correct 4 ms 716 KB Output is correct
7 Correct 3 ms 800 KB Output is correct
8 Correct 3 ms 716 KB Output is correct
9 Correct 3 ms 716 KB Output is correct
10 Correct 4 ms 716 KB Output is correct

Subtask #3
80.0 / 80.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 588 KB Output is correct
6 Correct 1 ms 588 KB Output is correct
7 Correct 1 ms 588 KB Output is correct
8 Correct 1 ms 588 KB Output is correct
9 Correct 1 ms 588 KB Output is correct
10 Correct 1 ms 588 KB Output is correct
11 Correct 3 ms 716 KB Output is correct
12 Correct 5 ms 716 KB Output is correct
13 Correct 3 ms 716 KB Output is correct
14 Correct 4 ms 716 KB Output is correct
15 Correct 4 ms 716 KB Output is correct
16 Correct 4 ms 716 KB Output is correct
17 Correct 3 ms 800 KB Output is correct
18 Correct 3 ms 716 KB Output is correct
19 Correct 3 ms 716 KB Output is correct
20 Correct 4 ms 716 KB Output is correct
21 Correct 51 ms 1484 KB Output is correct
22 Correct 191 ms 2788 KB Output is correct
23 Correct 108 ms 3484 KB Output is correct
24 Correct 161 ms 3476 KB Output is correct
25 Correct 101 ms 3404 KB Output is correct
26 Correct 122 ms 3396 KB Output is correct
27 Correct 328 ms 3500 KB Output is correct
28 Correct 322 ms 3484 KB Output is correct
29 Correct 239 ms 3480 KB Output is correct
30 Correct 108 ms 3496 KB Output is correct