#include <bits/stdc++.h>
#define mod 1000000007
using namespace std;
stack <pair<long long,long long>> S;
unsigned long long n,v[100005],i,dr[100005],st[100005],x,suma[100001],mars[100001],j,val,Max[100005];
pair <long long,long long > sor[100005];
long long total;
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;
}
sort(sor+1,sor+n+1);
for(i=1;i<=n;i++){
fin>>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});
}
for(i=1;i<=n;i++){
if(!dr[i])
dr[i] = n + 1;
}
for(i=1;i<=n;i++){
total += rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],sor[i].first) % mod;
total -= rectCount(suma[dr[sor[i].second]-1] - suma[st[sor[i].second]],Max[sor[i].second]) % mod;
for(j=st[sor[i].second];j<=dr[sor[i].second];j++){
Max[j] = sor[i].first;
}
}
cout << total % mod;
return 0;
}
Compilation message
fancyfence.cpp: In function 'int main()':
fancyfence.cpp:32:5: error: 'fin' was not declared in this scope; did you mean 'bin'?
32 | fin>>x;
| ^~~
| bin
fancyfence.cpp:37:34: warning: comparison of integer expressions of different signedness: 'long long unsigned int' and 'long long int' [-Wsign-compare]
37 | while(S.empty() == false && x<S.top().first){
| ~^~~~~~~~~~~~~~
fancyfence.cpp:48:35: warning: comparison of integer expressions of different signedness: 'long long unsigned int' and 'long long int' [-Wsign-compare]
48 | while(S.empty() == false && x < S.top().first){
| ~~^~~~~~~~~~~~~~~
