Submission #478310

#	Time	Username	Problem	Language	Result	Execution time	Memory
478310		Haruto810198	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	62 ms	10172 KiB

fancyfence

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define double long double

#define FOR(i, l, r, d) for(int i=(l); i<=(r); i+=(d))
#define szof(x) ((int)(x).size())

#define vi vector<int>
#define pii pair<int, int>

#define F first
#define S second

#define pb push_back
#define eb emplace_back
#define mkp make_pair

const int INF = 2147483647;
const int LNF = INF*INF;
const int MOD = 1000000007;
const int mod = 998244353;
const double eps = 1e-12;

//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")

const int MAX = 100010;

int n;
int h[MAX], w[MAX];
bool vis[MAX];

int p[MAX], dep[MAX];
int wsum[MAX], l[MAX], r[MAX];

int res;

int findp(int v){
    if(v == p[v]) return v;
    return p[v] = findp(p[v]);
}

void uni(int u, int v){

    int pu = findp(u);
    int pv = findp(v);
    if(pu == pv) return;
    if(dep[pu] < dep[pv]) swap(pu, pv);
    p[pv] = pu;
    if(dep[pu] > dep[pv]) dep[pu]++;

    wsum[pu] += wsum[pv];
    l[pu] = min(l[pu], l[pv]);
    r[pu] = max(r[pu], r[pv]);

}

signed main(){

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    //freopen("fancyfence_sample.txt", "r", stdin);

    cin>>n;
    FOR(i, 1, n, 1){
        cin>>h[i];
    }
    FOR(i, 1, n, 1){
        cin>>w[i];
    }

    FOR(i, 1, n, 1){
        vis[i] = 0;
        p[i] = i;
        dep[i] = 0;
        wsum[i] = w[i];
        l[i] = r[i] = i;
    }

    vector<pii> owo;
    FOR(i, 1, n, 1){
        owo.eb(h[i], i);
    }

    sort(owo.begin(), owo.end());
    reverse(owo.begin(), owo.end());

    for(pii i : owo){
        int id = i.S;
        vis[id] = 1;
        if(vis[id - 1]) uni(id - 1, id);
        if(vis[id + 1]) uni(id, id + 1);

        int U = h[id];
        int D = max(h[l[findp(id)] - 1], h[r[findp(id)] + 1]) + 1;
        int W = wsum[findp(id)] % MOD;
        res += (((U + D) * (U - D + 1) / 2) % MOD) * ((W * (W + 1) / 2) % MOD);
        res %= MOD;

        //cerr<<"U = "<<U<<", D = "<<D<<", res += "<<(((U + D) * (U - D + 1) / 2) % MOD) * ((W * (W + 1) / 2) % MOD)<<endl;
    }

    cout<<res<<'\n';

    return 0;

}

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