Submission #528278

#	Time	Username	Problem	Language	Result	Execution time	Memory
528278		Olympia	Fancy Fence (CEOI20_fancyfence)	C++17	12 / 100	1 ms	332 KiB

fancyfence

#include <cmath>
#include <cassert>
#include <iostream>
#include <set>
#include <climits>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <type_traits>
#include <string>
#include <queue>
#include <map>
#include <stack>

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma GCC optimization ("Ofast")
using namespace std;
const int MOD = 1e9 + 7;
int64_t mult (int64_t x, int64_t y) {
    return (x * y) % MOD;
}
int64_t c2 (int64_t x) {
    return (x * (x + 1)/2) % MOD;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int N;
    cin >> N;
    vector<int64_t> h(N), w(N);
    vector<pair<int64_t, int64_t>> grid(N);
    set<int> s;
    for (int i = 0; i < N; i++) {
        cin >> h[i];
        s.insert(h[i]);
    }
    vector<int64_t> pref = {0};
    for (int i = 0; i < N; i++) {
        cin >> w[i];
        pref.push_back(pref.back() + w[i]);
    }
    for (int i = 0; i < N; i++) {
        grid[i] = make_pair(w[i], h[i]);
    }
    int64_t ans = 0;
    for (int x: s) {
        for (int i = 0; i < N; i++) {
            if (h[i] == x) {
                int l = i;
                while (l >= 1) {
                    if (h[l - 1] >= x) {
                        l--;
                    } else {
                        break;
                    }
                }
                int r = i;
                while (r < N - 1) {
                    if (h[r + 1] > x) {
                        r++;
                    } else {
                        break;
                    }
                }
                //if (i == l || i == r) continue;
                //assert(l <= x && r >= x);
                int64_t sum = (pref[i] - pref[l]) * (pref[r + 1] - pref[i + 1]);
                sum += (pref[r + 1] - pref[l] - w[i]) * w[i];
                ans += sum * c2(x);
                ans %= MOD;
            }
        }
    }
    for (int i = 0; i < N; i++) {
        ans += mult(c2(grid[i].first), c2(grid[i].second));
        ans %= MOD;
    }
    cout << ans << '\n';
    return 0;
    ans = 0;
    for (int i = 0; i < N; i++) {
        ans += mult(c2(grid[i].first), c2(grid[i].second));
        ans %= MOD;
        int64_t min_w = grid[i].second;
        for (int j = i + 1; j < N; j++) {
            min_w = min(min_w, grid[j].second);
            ans += mult(c2(min_w), mult(grid[i].first, grid[j].first));
            ans %= MOD;
        }
    }
    cout << ans << '\n';
}

Compilation message (stderr)

fancyfence.cpp:16: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   16 | #pragma GCC optimization ("O3")
      | 
fancyfence.cpp:17: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   17 | #pragma GCC optimization ("unroll-loops")
      | 
fancyfence.cpp:18: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   18 | #pragma GCC optimization ("Ofast")
      |

• Subtask 1: 0 / 0
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 18
• Subtask 7: 0 / 27