Submission #375545

#	Time	Username	Problem	Language	Result	Execution time	Memory
375545		spatarel	Skyscraper (JOI16_skyscraper)	C++17	100 / 100	211 ms	6764 KiB

skyscraper

#include <stdio.h>
#include <algorithm>
 
const int MOD = 1000000007;
 
const int MAX_N = 100;
const int MAX_L = 1000;
 
long long Count[2][1 + MAX_N + 1][1 + MAX_L][1 + 2 + 1];
 
void addSelf(long long &a, long long b) {
  a = (a + b) % MOD;
}

int main() {
  int N, L;
  scanf("%d%d", &N, &L);
  int A[1 + N];
  for (int i = 1; i <= N; i++) {
    scanf("%d", &A[i]);
  }
  A[0] = A[1];
  std::sort(A + 1, A + N + 1);
  Count[0][0][0][0] = 1;
  int I = 0;
  int newI = 1;
  for (int i = 0; i + 1 <= N; i++) {
    for (int d = 0; d <= N; d++) {
      for (int l = 0; l <= L; l++) {
        for (int e = 0; e <= 2; e++) {
          Count[newI][d][l][e] = 0;
        }
      }
    }
    for (int d = 0; d <= N; d++) {
      for (int l = 0; l <= L; l++) {
        for (int e = 0; e <= 2; e++) {
          int newL = l+(2*d-e)*(A[i+1]-A[i]);
          if (0 <= newL && newL <= L) {
            addSelf(Count[newI][d + 1][newL][e]    , (d+1-e) * Count[I][d][l][e]); // valley
            if (0 <= d - 1) {
            addSelf(Count[newI][d - 1][newL][e]    , (d-1)   * Count[I][d][l][e]); // peak
            }
            addSelf(Count[newI][d + 0][newL][e]    , (2*d-e) * Count[I][d][l][e]); // edge
            addSelf(Count[newI][d + 0][newL][e + 1], (2-e)   * Count[I][d][l][e]); // edge ending
            addSelf(Count[newI][d + 1][newL][e + 1], (2-e)   * Count[I][d][l][e]); // valley ending
          }
        }
      }
    }
    std::swap(I, newI);
  }
  long long answer = 0;
  for (int l = 0; l <= L; l++) {
    addSelf(answer, Count[N % 2][1][l][2]);
  }
  if (N == 1) {
    answer = 1;
  }
  printf("%lld\n", answer);
  return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:17:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 |   scanf("%d%d", &N, &L);
      |   ~~~~~^~~~~~~~~~~~~~~~
skyscraper.cpp:20:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   20 |     scanf("%d", &A[i]);
      |     ~~~~~^~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80