Submission #444991

#	Time	Username	Problem	Language	Result	Execution time	Memory
444991		Khizri	Fancy Fence (CEOI20_fancyfence)	C++17	58 / 100	1086 ms	6544 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
//------------------------------DEFINE------------------------------
//******************************************************************
#define IOS ios_base::sync_with_stdio(false); cin.tie(0),cout.tie(0)
#define ll long long
#define pb push_back		 
#define F first																 
#define S second 															 
#define INF 1e18
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pii pair<int,int>
#define pll pair<ll,ll>
#define OK cout<<"Ok"<<endl;
#define MOD (ll)(1e9+7)
#define endl "\n"
//******************************************************************
//----------------------------FUNCTION------------------------------
//******************************************************************
ll gcd(ll a,ll b){
	if(a>b) swap(a,b);
	if(a==0) return a+b;
	return gcd(b%a,a);
}
ll lcm(ll a,ll b){
	return a/gcd(a,b)*b;
}
bool is_prime(ll n){
	ll k=sqrt(n);
	if(n==2) return true;
	if(n<2||n%2==0||k*k==n) return false;
	for(int i=3;i<=k;i+=2){
		if(n%i==0){
			return false;
		}
	}
	return true;
}
//*****************************************************************
//--------------------------MAIN-CODE------------------------------
const int mxn=2e5+5;
ll t=1,n,arr[mxn],h[mxn];
ll cal(ll k,ll sum){
	sum=sum%MOD;
	ll a=k;
	ll b=k+1;
	if(a%2==0){
		a/=2;
	}
	else{
		b/=2;
	}
	ll x=(a*b)%MOD;
	a=sum;
	b=sum+1;
	if(a%2==0){
		a/=2;
	}
	else{
		b/=2;
	}
	ll y=(a*b)%MOD;
	ll ans=(x*y)%MOD;
	return ans;
}
void solve(){
	ll ans=0;
	ll sum=0,k=0;
	set<ll>st;
	cin>>n;
	bool q=true;
	for(int i=1;i<=n;i++){
		cin>>h[i];
		st.insert(h[i]);
		if(i>1&&h[i]!=h[i-1]){
			q=false;
		}
	}
	for(int i=1;i<=n;i++){
		cin>>arr[i];
		sum+=arr[i];
	}
	if(q){
		cout<<cal(h[1],sum)<<endl;
		return;
	}
	ll x=0;
	for(ll k:st){
		ll sum=0;
		for(int i=1;i<=n;i++){
			if(h[i]<k){
				if(sum>0){
					ll say=cal(k,sum)-cal(x,sum);
					if(say<0){
						say+=MOD;
					}
					ans=(ans+say)%MOD;
					sum=0;
				}
			}
			else{
				sum+=arr[i];
			}
		}
		if(sum>0){
			ll say=cal(k,sum)-cal(x,sum);
			if(say<0){
				say+=MOD;
			}
			ans=(ans+say)%MOD;
			sum=0;
		}
		x=k;
	}
	cout<<ans<<endl;
}
int main(){
	IOS;
	//cin>>t;
	while(t--){
		solve();
	}
	return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'void solve()':
fancyfence.cpp:69:11: warning: unused variable 'k' [-Wunused-variable]
   69 |  ll sum=0,k=0;
      |           ^

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