Submission #592133

#	Time	Username	Problem	Language	Result	Execution time	Memory
592133		jasmin	Fancy Fence (CEOI20_fancyfence)	C++14	100 / 100	206 ms	28972 KiB

fancyfence

#include<bits/stdc++.h>
using namespace std;
#define int long long

const int mod=1e9+7;

struct node{
    int left=0;
    int right=0;
    int ans=0;
    int sum=1;
};
node zero={0, 0, 0, 0};

struct segtree{
    vector<node> tree;

    segtree(int n){
        tree.resize(n*4);
        build(0, n, 0);
    };

    node build(int l, int r, int v){
        if(l+1==r){
            tree[v].left=tree[v].right=0;
            tree[v].sum=1;
            tree[v].ans=0;
            return tree[v];
        }
        int m=l+(r-l)/2;
        return tree[v]=merge(build(l, m, v*2+1), build(m, r, v*2+2));
    }

    node merge(node a, node b){
        node ret;
        ret.sum=(a.sum+b.sum)%mod;
        ret.ans=(a.ans+b.ans)%mod;
        ret.left=a.left;
        ret.right=b.right;

        int middle=(a.right+b.left)%mod;
        if(a.left==a.sum){
            middle=0;
            ret.left=(a.sum+b.left)%mod;
        }
        if(b.right==b.sum){
            middle=0;
            ret.right=(a.right+b.sum)%mod;
        }

        ret.ans+=(middle*(middle+1)/2)%mod;
        ret.ans%=mod;

        return ret;
    }

    node update(int l, int r, int v, int x, int val){
        //cout << "update " << l << " " << r << " " << v << " " << x << " " << val << "\n";
        if(x<l || r<=x) {
            //cout << l << " " << r << " " << v << ": " << tree[v].left << " " << tree[v].right << " " << tree[v].sum << " " << tree[v].ans << "\n";
            return tree[v];
        }
        if(l+1==r){
            tree[v].left=val;
            tree[v].right=val;
            tree[v].sum=val;
            tree[v].ans=0;
            //cout << l << " " << r << " " << v << ": " << tree[v].left << " " << tree[v].right << " " << tree[v].sum << " " << tree[v].ans << "\n";
            return tree[v];
        }
        int m=l+(r-l)/2;
        tree[v]=merge(update(l, m, v*2+1, x, val), update(m, r, v*2+2, x, val));
        //cout << l << " " << r << " " << v << ": " << tree[v].left << " " << tree[v].right << " " << tree[v].sum << " " << tree[v].ans << "\n";
        return tree[v];
    }
    node query(int l, int r, int v, int ql, int qr){
        if(qr<=l || r<=ql) return zero;
        if(ql<=l && r<=qr) return tree[v];
        int m=l+(r-l)/2;
        return merge(query(l, m, v*2+1, ql, qr), query(m, r, v*2+2, ql, qr));
    }
    
};

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    vector<int> h(n);
    map<int,int> ind; int x=1;
    vector<pair<int, vector<int> > >sorted;
    sorted.push_back({0, {}});
    for(int i=0; i<n; i++){
        cin >> h[i];
        if(ind[h[i]]==0){
            sorted.push_back({h[i], {}});
            ind[h[i]]=x;
            x++;
        }
        sorted[ind[h[i]]].second.push_back(i);
    }
    sort(sorted.begin(), sorted.end());
    reverse(sorted.begin(), sorted.end());
    vector<int> w(n);
    for(int i=0; i<n; i++){
        cin >> w[i];
    }

    
    int ans=0;
    segtree seg(n);
    for(int i=0; i<(int)sorted.size()-1; i++){
        int h=sorted[i].first;
        int next=sorted[i+1].first;

        vector<int> ele=sorted[i].second;
        for(auto e: ele){
            seg.update(0, n, 0, e, w[e]);
        }

        node res=seg.query(0, n, 0, 0, n);
        //cout << res.ans << " " << res.left << " " << res.right << "\n";
        int s=res.ans;
        s+= (res.left*(res.left+1)/2)%mod;
        s%=mod;
        if(res.right!=res.sum){
            s+=(res.right*(res.right+1)/2)%mod;
            s%=mod;
        }

        int factor=((h*(h+1))/2 - (next*(next+1))/2)%mod;
        //cout << factor << " " << s << "\n";
        ans+=(s*factor)%mod;
        ans%=mod;
    }

    cout << ans << "\n";
}

• 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