Submission #549516

#	Time	Username	Problem	Language	Result	Execution time	Memory
549516		theshadow_04	Skyscraper (JOI16_skyscraper)	C++14	5 / 100	413 ms	206160 KiB

skyscraper

// annotshy

#include <bits/stdc++.h>

#define Task "CF"
#define MOD 1000000007
#define pb push_back

using namespace std;

const int maxn = 200005;

int n, l;
int a[maxn];
int dp[(1 << 14) + 5][15][105];

void Sub1() {
  vector<int> v;
  for(int i = 1; i <= n; ++i) cin >> a[i], v.pb(i);
  int ans = 0;
  do {
    long long res = 0;
    for(int i = 0; i < (int) v.size() - 1; ++ i) res += abs(a[v[i + 1]] - a[v[i]]);
    if(res <= l) ++ ans;
    if(ans > MOD) ans -= MOD;
  } while(next_permutation(v.begin(), v.end()));
  cout << ans << "\n";
}

void Solve(int Test) {
  cin >> n >> l;
  if(n <= 8) {
    Sub1();
    return;
  }
  for(int i = 0; i < n; ++ i) cin >> a[i];
  memset(dp, 0, sizeof dp);
  for(int i = 0; i < n; ++ i) {
    dp[(1 << i)][i][0] = 1;
  }
  for(int mask = 0; mask < (1 << n); ++ mask) {
    for(int last = 0; last < n; ++ last) {
      for(int s = 0; s <= l; ++ s) {
        if(dp[mask][last][s] == 0 || !(mask >> last & 1)) continue;
        for(int nex = 0; nex < n; ++ nex) {
          if(mask >> nex & 1 && s + abs(a[last] - a[nex]) <= l) continue;
          (dp[mask + (1 << nex)][nex][s + abs(a[last] - a[nex])] += dp[mask][last][s]) %= MOD;
        }
      }
    }
  }
  int ans = 0;
  for(int last = 0; last < n; ++ last) {
    for(int s = 0; s <= l; ++ s) {
      (ans += dp[(1 << n) - 1][last][s]) %= MOD;
    }
  }
  cout << ans << "\n";
}

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  if(fopen(Task".inp", "r")) {
    freopen(Task".inp", "r", stdin);
    freopen(Task".out", "w", stdout);
  }
  int test = 1;
  // cin >> test;
  for(int i = 1; i <= test; ++ i) {
    Solve(i);
  }
}

/*no pain no gain*/

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen(Task".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:66:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     freopen(Task".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 80