#include<bits/stdc++.h>
//#include "grader.h"
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define ld long double
#define st first
#define nd second
#define pb push_back
#define INF INT_MAX
using namespace std;
const int N = 1e5 + 10;
const int M = 1e9+7;
stack<pll> s;
ll h[N], w[N];
ll add(ll a, ll b) {return (((a+b)%M)+M)%M;}
ll mul(ll a, ll b) {return (a%M*b%M)%M;}
ll power(ll a, ll b) {
if (b == 0) return 1;
ll ret = power(a, b/2);
if (b&1) return mul(mul(ret, ret), a);
else return mul(ret, ret);
}
void solve() {
int n; cin >> n;
for (int i = 1; i <= n; ++i) cin >> h[i];
for (int i = 1; i <= n; ++i) cin >> w[i];
ll ans = 0;
ll inv = power(2, M-2);
s.push({0, 0});
for (int i = 1; i <= n; ++i) {
while (s.top().st > h[i]) {
int H = s.top().st;
int W = s.top().nd;
s.pop();
if (h[i] > s.top().st) {
H -= h[i];
w[i] += W;
}
else {
auto [a, b] = s.top(); s.pop();
s.push({a, b+W});
H -= s.top().st;
}
ans = add(ans, mul(mul(mul(H, H+1), inv), mul(mul(W, W+1), inv)));
ans = add(ans, mul(mul(H, s.top().st), mul(mul(W, W+1), inv)));
}
if (s.top().st == h[i]) {
auto [a, b] = s.top(); s.pop();
s.push({a, b+w[i]});
}
else s.push({h[i], w[i]});
}
while (s.size() > 1) {
int H = s.top().st;
int W = s.top().nd;
s.pop();
auto [a, b] = s.top(); s.pop();
s.push({a, b+W});
H -= s.top().st;
ans = add(ans, mul(mul(mul(H, H+1), inv), mul(mul(W, W+1), inv)));
ans = add(ans, mul(mul(H, s.top().st), mul(mul(W, W+1), inv)));
}
cout << ans << '\n';
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(NULL);
int t = 1;
// cin >> t;
while (t--) {
solve();
}
return 0;
}
Compilation message
fancyfence.cpp: In function 'void solve()':
fancyfence.cpp:46:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
46 | auto [a, b] = s.top(); s.pop();
| ^
fancyfence.cpp:54:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
54 | auto [a, b] = s.top(); s.pop();
| ^
fancyfence.cpp:63:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
63 | auto [a, b] = s.top(); s.pop();
| ^
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
324 KB |
Output is correct |
2 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |