#include "bits/stdc++.h"
#pragma optimize ("Bismillahirrahmanirrahim")
using namespace std;
#define pb push_back
#define ff first
#define ss second
#define endl "\n"
#define int long long
#define double long double
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define what_is(x) cerr << #x << " is " << x << endl;
//#define m (l+r)/2
constexpr int N=200005;
constexpr int MOD=1000000007;
constexpr int INF2 = LLONG_MAX;
constexpr int INF=(int)1e18;
constexpr int LOG=30;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tp;
typedef priority_queue<pii,vector<pii>,greater<pii>> min_pq;
typedef priority_queue<pii> max_pq;
typedef long long ll;
//to think//
/*
* graph approach
* dp
* dividing the problem to smaller statements
* finding the real constraint
* sqrt decomposition
* greedy approach
* pigeonhole principle
* rewriting the problem/equality
* bitwise approaches
* binary search if monotonic
* divide and conquer
* combinatorics
* inclusion - exclusion
* think like bfs
*/
inline int in()
{
int x;cin >> x;
return x;
}
inline string in2()
{
string x;cin >> x;
return x;
}
int add(int a,int b)
{
if(a+b>=MOD) return a+b-MOD;
return a+b;
}
int mult(int a,int b)
{
if(a*b>=MOD) return (a*b)%MOD;
return a*b;
}
int eks(int a,int b)
{
if(a<b) return a-b+MOD;
return a-b;
}
int fast(int a,int b)
{
if(b==0) return 1;
int res=fast(a,b/2);
res=mult(res,res);
if(b&1) res=mult(res,a);
return res;
}
void solve()
{
int n=in(),ans=0;
array<int,2> ar[n+1];
ar[0]=ar[n+1]={0,0};
for(int i=1;i<=n;i++) ar[i][0]=in();
for(int i=1;i<=n;i++) ar[i][1]=in();
int pre[n+1];
pre[0]=0;
int xd=fast(2,MOD-2);
auto get=[&](int a){
return mult(xd,mult(a,eks(a,1LL)));
};
for(int i=1;i<=n;i++) pre[i]=add(pre[i-1],ar[i][1]);
array<int,2> hist[n+1];
stack<int> s;
for(int i=1;i<=n;i++)
{
while(!s.empty() && ar[s.top()][0]>=ar[i][0]) s.pop();
hist[i][0]=s.empty() ? 0 : s.top();
s.push(i);
}
while(!s.empty()) s.pop();
for(int i=n;i>=1;i--)
{
while(!s.empty() && ar[s.top()][0]>=ar[i][0]) s.pop();
hist[i][1]=s.empty() ? n+1 : s.top();
s.push(i);
}
while(!s.empty()) s.pop();
map<pii,bool> mp;
for(int i=1;i<=n;i++)
{
if(mp[{ar[i][0],hist[i][0]}]) continue;
mp[{ar[i][0],hist[i][0]}]=1;
int r=hist[i][1];
int l=hist[i][0];
int maxi=max(ar[l][0],ar[r][0]);
int uz=add(1LL,eks(pre[r-1],pre[l]));
//cout << maxi << endl;
ans=add(ans,mult(get(uz),get(add(ar[i][0]-maxi,1LL))));
ans=add(ans,mult(get(uz),mult(ar[i][0]-maxi,maxi)));
}
cout << ans << endl;
}
int32_t main(){
cin.tie(0); ios::sync_with_stdio(0);
cout << fixed << setprecision(15);
int t=1;//cin>> t;
for(int i=1;i<=t;i++)
{
// cout << "Case #" << i << ": ";
solve();
}
return 0;
}
Compilation message
fancyfence.cpp:2: warning: ignoring '#pragma optimize ' [-Wunknown-pragmas]
2 | #pragma optimize ("Bismillahirrahmanirrahim")
|
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
388 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
320 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
388 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
