#include<bits/stdc++.h>
#define vi vector<int>
#define vll vector<long long int>
#define vpii vector<pair<int,int>>
#define vpll vector<pair<long long int, long long int>>
#define pb push_back
#define f0r(i,n) for(int i = 0;i<n;i++)
using namespace std;
typedef long long int ll;
const int mod = 1e9 + 7;
const int mxn = 1e5 + 5;
const int lg = floor(log2(mxn));
ll w[mxn];
ll h[mxn];
ll minh[lg][mxn];
ll ans(ll w, ll h){
return c2(w) * c2(h) % mod;
}
ll c2(ll x){
return x * (x+1) / 2 % mod;
}
ll minq(int l, int r){
int sz = r - l + 1;
int curlg = floor(log2(sz));
return min(minh[curlg][l], minh[curlg][r - (int)pow(2, curlg) + 1]);
}
int main(){
int n;
cin>>n;
f0r(i,n)cin>>h[i];
f0r(i,n)cin>>w[i];
f0r(i,n)minh[0][i] = h[i];
for(int l = 1;l<=floor(log2(n));l++){
f0r(i, n - pow(l, 2) + 1){
minh[l][i] = min(minh[l-1][i], minh[l-1][i + (int)pow(l-1, 2)]);
}
}
ll dp[n+1];
dp[0] = ans(w[0], h[0]);
for(int i = 1;i<n;i++){
ll rm = h[i];
ll thing = 0;
for(int j = i-1;j>=0;j--){
rm = min(rm, h[j]);
thing += c2(rm) * w[j] % mod;
}
dp[i] = ((dp[i-1] + ans(w[i], h[i])) % mod + ((w[i] * thing) % mod)) % mod;
}
//for(auto u : dp)cout<<u<<' ';
//cout<<'\n';
cout<<dp[n-1];
}
Compilation message
fancyfence.cpp: In function 'll ans(ll, ll)':
fancyfence.cpp:17:12: error: 'c2' was not declared in this scope
17 | return c2(w) * c2(h) % mod;
| ^~
