Submission #791388

#	Time	Username	Problem	Language	Result	Execution time	Memory
791388		peteza	Fancy Fence (CEOI20_fancyfence)	C++14	0 / 100	1 ms	340 KiB

fancyfence

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;

ll n, h[100005], w[100005];
stack<pll> stk;

ll mod = 1e9+7;
ll cans = 0, csum = 0;

void upd(ll&x){
    if(x<0) x += mod;
    if(x >= mod) x-=mod;
}

int main() {
    cin.tie(0) -> sync_with_stdio(0);
    cin >> n;
    for(int i=0;i<n;i++) cin >> h[i];
    for(int i=0;i<n;i++) cin >> w[i];
    for(int i=0;i<n;i++) {
        cans += (((h[i]+1)*h[i]/2)%mod)*(((w[i]+1)*w[i]/2)%mod)%mod; upd(cans);
        ll cw = w[i];
        while(!stk.empty() && stk.top().first > h[i]) {
            cw += stk.top().second;
            csum -= ((1ll*stk.top().first*stk.top().second) % mod);
            upd(csum);
            stk.pop();
        }
        cans += w[i]*csum%mod; upd(cans);
        stk.emplace(h[i], cw);
        csum += cw*h[i]%mod; upd(csum);
        //cout << cans;
    }
    cout << cans;
}

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