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Submission #576720

# Submission time Handle Problem Language Result Execution time Memory
576720 2022-06-13T10:48:11 Z timreizin Fancy Fence (CEOI20_fancyfence) C++17
0 / 100
 1 ms 340 KB 
#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <iomanip>
#include <cmath>
#include <stack>
#include <numeric>

using namespace std;

using ll = long long;

const ll MOD = 1e9 + 7;

ll asum(ll n)
{
    return ((n * (n + 1)) / 2) % MOD;
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    //freopen("/Users/timreizin/Downloads/sample/input1.txt", "r", stdin);
    int n;
    cin >> n;
    vector<ll> h(n), w(n);
    for (ll &i : h) cin >> i;
    for (ll &i : w) cin >> i;
    vector<ll> pref(n + 1);
    partial_sum(w.begin(), w.end(), pref.begin() + 1);
    vector<int> sl(n, -1), sr(n, n);
    stack<int> help;
    for (int i = 0; i < n; ++i)
    {
        while (!help.empty() && h[help.top()] >= h[i]) help.pop();
        if (!help.empty()) sl[i] = help.top();
        help.push(i);
    }
    while (!help.empty()) help.pop();
    for (int i = n - 1; i >= 0; --i)
    {
        while (!help.empty() && h[help.top()] > h[i]) help.pop();
        if (!help.empty()) sl[i] = help.top();
        help.push(i);
    }
    ll res = 0;
    for (int i = 0; i < n; ++i)
    {
        res = (res + asum(h[i]) * asum(w[i])) % MOD;
        ll l1 = (pref[i] - pref[sl[i] + 1]) % MOD;
        if (l1 < 0) l1 += MOD;
        ll l2 = (pref[sr[i]] - pref[i + 1]) % MOD;
        if (l2 < 0) l2 += MOD;
        ll sum = (l1 + 1) * (l2 + 1) % MOD - 1;
        if (sum < 0) sum += MOD;
        res = (res + sum * asum(h[i])) % MOD;
    }
    cout << res;
    return 0;
}

Subtask #1
0.0 / 0.0

# 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 -

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 212 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 13.0

# 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 -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 340 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 320 KB Output is correct
2 Incorrect 1 ms 332 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 320 KB Output is correct
2 Incorrect 1 ms 340 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 27.0

# 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 -