#include <bits/stdc++.h>
#define mod 1000000007
using namespace std;
stack <pair<int,int>> S;
int n,v[100005],i,dr[100005],st[100005],x,j,val,Max;
long long suma[100001],total1,val1, val2,total2;
pair <int,int > sor[100005];
long long bin(long long x){
x %= mod;
return ((x*(x+1))/2)%mod;
}
long long rectCount(long long x, long long y){
return (bin(x)*bin(y))%mod;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>n;
for(i=1;i<=n;i++){
cin>>v[i];
sor[i].first = v[i];
sor[i].second = i;
dr[i] = n + 1;
}
sort(sor+1,sor+n+1);
for(i=1;i<=n;i++){
cin>>x;
suma[i] = suma[i-1] + x;
}
for(i=1;i<=n;i++){
x = v[i];
while(S.empty() == false && x<S.top().first){
dr[S.top().second] = i;
S.pop();
}
S.push({x,i});
}
while(S.empty() == false){
S.pop();
}
for(i=n;i>=1;i--){
x = v[i];
while(S.empty() == false && x < S.top().first){
st[S.top().second] = i;
S.pop();
}
S.push({x,i});
}
//brut
for(i=1;i<=n;i++){
total1 = (total1 + rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],sor[i].first)) % mod;
for(j=i-1;j>=1;j--){
if(st[sor[j].second] <= sor[i].second && dr[sor[j].second] >= sor[i].second){
Max = sor[j].first;
break;
}
}
total2 = (total2 + rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],Max)) % mod;
}
if(total1 < total2)
total1 += mod;
cout << total1 - total2 << endl;
return 0;
Compilation message
fancyfence.cpp: In function 'int main()':
fancyfence.cpp:70:13: error: expected '}' at end of input
70 | return 0;
| ^
fancyfence.cpp:22:1: note: to match this '{'
22 | {
| ^
