Submission #1234947

#	Time	Username	Problem	Language	Result	Execution time	Memory
1234947		veehj	Fancy Fence (CEOI20_fancyfence)	C++17	0 / 100	1 ms	328 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
#define pb push_back
#define sz(a) (ll) a.size()
#define all(x) (x).begin(), (x).end()
#define rep(i, a, b) for(ll i=(ll)(a); i<(ll)(b); i++)
#define rrep(i, a, b) for(ll i=(ll)(a); i>=(ll)(b); i--)
#define vl vector<ll>
#define vpll vector<pair<ll, ll>>
#define vvl vector<vector<ll>>
#define pll pair<ll, ll>
const ll md=1e9+7;

ll cnt(ll a, ll b){
  ll ret=((((a+1)*(a))/2 % md) * ((((b+1)%md)*(b))/2 % md)) % md;
  return ret;
}

void f() {
  ll n; cin >> n; ll cntw=0;
  vl h(n), w(n); 
  for(auto& u : h) cin >> u;
  for(auto& u : w){ cin >> u; cntw+=u; }
  ll ans=cnt(1, (cntw%md));
  ans%=md;
  ll strt=-1;
  rep(i, 0, n){
    if(h[i]==2){
      strt=i;
      break;
    }
  }
  if(strt==-1){
    cout << ans;
    return;
  }
  bool two=1; ll sm=w[strt];
  rep(i, strt+1, n){
    if(((h[i]==2) == two) && two){
      sm+=w[i];
    } else if(((h[i]==2) == two) && !two){
      continue;
    } else if(h[i]==2){
      sm=w[i];
      two=1;
    } else {
      sm=0;
      ans+=2*cnt(1, sm);
      two=0;
      ans%=md;
    }
  }
  if(h[n-1]==2){
    ans+=2*cnt(1, sm);
    ans%=md;
  }
  cout << ans;
}

int main() {
  int tc=1;
  while (tc--) f();
}

• Subtask 1: 0 / 0
• Subtask 2: 0 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 18
• Subtask 7: 0 / 27