#include <iostream>
#include <cassert>
#include <cstring>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <utility>
#include <array>
using i64 = long long;
using u64 = unsigned long long;
using f64 = double;
using f80 = long double;
using namespace std;
#define ALL(x) x.begin(), x.end()
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false);
#define N 200005
int main()
{
constexpr i64 mod { 1000000007 };
ShinLena;
int n;
cin >> n;
vector<int> h(n+1), w(n+1), l(n+1), r(n+1), p(n+1);
vector<i64> ww(n+1);
for (int i = 1; i <= n; ++i) cin >> h[i];
for (int i = 1; i <= n; ++i) cin >> w[i], ww[i] = ww[i-1] + w[i];
for (int i = 1; i <= n; ++i)
{
p[i] = i - 1;
while (h[p[i]] > h[i])
p[i] = p[p[i]];
l[i] = r[p[i]];
r[p[i]] = i;
p[l[i]] = i;
}
i64 ans = 0;
auto dfs = [&](auto &&dfs, int u, int ll, int rr)
{
if (!u) return;
if (ll > rr) return;
i64 w1 = ww[rr] - ww[ll-1];
auto C2 = [](i64 x) { return x * (x+1) % mod * 500000004ll % mod; };
(ans += C2(w1) * h[u] % mod) %= mod;
dfs(dfs, l[u], ll, u-1);
dfs(dfs, r[u], u+1, rr);
};
for (int i = 1; i <= n; ++i) if (!p[i]) dfs(dfs, i, 1, n);
cout << ans << '\n';
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
1 ms |
344 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
1 ms |
344 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Incorrect |
1 ms |
344 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |