Submission #827450

#	Time	Username	Problem	Language	Result	Execution time	Memory
827450		PagodePaiva	Fancy Fence (CEOI20_fancyfence)	C++14	12 / 100	2 ms	340 KiB

fancyfence

#include<bits/stdc++.h>
#define pii pair <int, int>
#define fr first
#define sc second
#define N 100010
#define inf 1e18
#define int long long

using namespace std;

int n;
int h[N], w[N];
int pref[N];
const int mod = 1e9+7;

struct Segtree{
    pair <int,int> tree[4*N];

    pair <int,int> join(pii a, pii b){
        if(a.fr < b.fr) return a;
        if(a.fr > b.fr) return b;
        if(a.sc < b.sc) return a;
        return b;
    }

    void build(int l, int r, int node){
        if(l == r){
            tree[node] = {h[l], l};
            return;
        }

        int mid = (l+r)/2;

        build(l, mid, 2*node);
        build(mid+1, r, 2*node+1);

        tree[node] = join(tree[2*node], tree[2*node+1]);

        return;
    }

    pair <int, int> query(int l, int r, int tl, int tr, int node){
        if(tl > r or tr < l) return {inf, inf};
        if(l <= tl and tr <= r) return tree[node];

        int mid = (tl+tr)/2;

        return join(query(l, r, tl, mid, 2*node), query(l, r, mid+1, tr, 2*node+1));
    }
} seg;

int query(int l, int r, int minant){
    int c = pref[r] - pref[l-1];
    int a = seg.query(l, r, 1, n, 1).fr;

    int res = (c-1)*(a-1)*c*a;
    res /= 4;
    res += ((a+c-2)*a*c)/2;
    res += a*c;

    a = minant;
    int res2 = (c-1)*(a-1)*c*a;
    res2 /= 4;
    res2 += ((a+c-2)*a*c)/2;
    res2 += a*c;

    res -= res2;

    // cout << res << "\n";

    return res % mod;
}

int32_t main(){
    cin >> n;

    for(int i = 1;i <= n;i++){
        cin >> h[i];
    }

    for(int i = 1;i <= n;i++){
        cin >> w[i];
    }

    seg.build(1, n, 1);

    queue <array <int,4>> q;
    q.push({1, n, 0, 0});

    for(int i = 1;i <= n;i++){
        pref[i] = pref[i-1] + w[i];
    }

    int res = 0;

    while(!q.empty()){
        auto [l, r, minant, aux] = q.front();
        q.pop();

        if(aux == 0){
            res += query(l, r, minant); res %= mod;
            auto [minn, pos] = seg.query(l, r, 1, n, 1);

            if(pos != l) q.push({l, pos-1, minn, 0});
            if(pos != r) q.push({pos+1, r, minn, 1});
        }

        else{
            auto [minn, pos] = seg.query(l, r, 1, n, 1);
            if(minant == minn){
                if(pos != l) q.push({l, pos-1, minn, 0});
                if(pos != r) q.push({pos+1, r, minn, 1});       
            }
            else{
                q.push({l, r, minant, 0});
            }
        }
    }

    cout << res << '\n';

    return 0;
}

Compilation message (stderr)

fancyfence.cpp: In function 'int32_t main()':
fancyfence.cpp:97:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   97 |         auto [l, r, minant, aux] = q.front();
      |              ^
fancyfence.cpp:102:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  102 |             auto [minn, pos] = seg.query(l, r, 1, n, 1);
      |                  ^
fancyfence.cpp:109:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  109 |             auto [minn, pos] = seg.query(l, r, 1, n, 1);
      |                  ^

• 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