#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;
cin>>n;
bool q=true;
for(int i=1;i<=n;i++){
cin>>h[i];
}
for(int i=1;i<=n;i++){
cin>>arr[i];
sum+=arr[i];
}
stack<pll>st;
st.push({h[1],arr[1]});
for(int i=2;i<=n;i++){
ll x=0;
while(st.size()&&h[i]<st.top().F){
ll say=cal(st.top().F,st.top().S)-cal(h[i],st.top().S);
if(say<0){
say+=MOD;
}
ans=(ans+say)%MOD;
x+=st.top().S;
st.pop();
}
st.push({h[i],x+arr[i]});
}
vector<pll>vt;
while(st.size()){
vt.pb(st.top());
st.pop();
}
vt.pb({0,0});
reverse(all(vt));
for(int i=0;i<vt.size();i++){
ll say=cal(vt[i].F,sum)-cal(vt[i-1].F,sum);
if(say<0){
say+=MOD;
}
ans=(ans+say)%MOD;
sum-=vt[i].S;
}
cout<<ans<<endl;
}
int main(){
IOS;
//cin>>t;
while(t--){
solve();
}
return 0;
}
Compilation message
fancyfence.cpp: In function 'void solve()':
fancyfence.cpp:101:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
101 | for(int i=0;i<vt.size();i++){
| ~^~~~~~~~~~
fancyfence.cpp:69:11: warning: unused variable 'k' [-Wunused-variable]
69 | ll sum=0,k=0;
| ^
fancyfence.cpp:71:7: warning: unused variable 'q' [-Wunused-variable]
71 | bool q=true;
| ^
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
204 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
288 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
280 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
204 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
