Submission #923960

#	Time	Username	Problem	Language	Result	Execution time	Memory
923960		treap_enjoyer	Fancy Fence (CEOI20_fancyfence)	C++14	0 / 100	1 ms	556 KiB

fancyfence

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("Ofast,unroll-loops")

#define ll long long
#define all(x) x.begin(), x.end()
#define ld long double
#define pii pair<int, int>
#define int long long
using namespace std;
using namespace __gnu_pbds;

template<class T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const int INF = 1e9 + 7;
const int MAXN = 1e5 + 5;
ll bin_pow(int a, int b){
    if(!b) return 1;
    if(b & 1) return (a * bin_pow(a, b - 1)) % INF;
    else return bin_pow((a * a) % INF, b / 2);
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    // ifstream cin("input.txt");
    // ofstream cout("output.txt");
    int n;
    cin >> n;
    vector<int> h(n + 1);
    vector<int> w(n + 1);
    bool flg = 1;
    for(int i = 1; i <= n; i++){
        cin >> h[i];
        if(i != 1 && h[i] != h[i - 1]) flg = 0;
    }
    for(int i = 1; i <= n; i++){
        cin >> w[i];
    }
    vector<ll> dp(n + 1, 0);
    stack<pair<int, int> > st;
    st.push({0, 0});
    vector<ll> pref(n + 1);
    for(int i = 1; i <= n; i++){
        pref[i] += pref[i - 1];
        pref[i] += w[i];
        pref[i] %= INF;
    }
    vector<int> ans(n + 1, 0);
    for(int i = 1; i <= n; i++){
        while(st.top().first >= h[i]){
            st.pop();   
        }
        ll sumw = pref[i] - pref[st.top().second];
        ll x = 0;
        x = h[i];
        x *= h[i] + 1;
        x %= INF;
        x *= bin_pow(2, INF - 2);
        x %= INF;
        x *= sumw;
        x %= INF;
        dp[i] += dp[st.top().second];
        dp[i] %= INF;
        dp[i] += x;   
        dp[i] %= INF;
        ans[i] += ans[i - 1];
        ans[i] += dp[i];
        ans[i] += dp[st.top().second] * (w[i] - 1);
        ans[i] %= INF;
        x = 1;
        x *= h[i];
        x %= INF;
        x *= h[i] + 1;
        x %= INF;
        x *= bin_pow(2, INF - 2);
        x %= INF; 
        x *= sumw - w[i];
        x *= w[i] - 1;
        x %= INF;
        ans[i] += x;
        ans[i] %= INF;
        x = 1;
        x *= h[i] + 1;
        x %= INF;
        x *= h[i];
        x %= INF;
        x *= bin_pow(2, INF - 2);
        x %= INF;
        x *= w[i] - 1;
        x %= INF;
        x *= w[i];
        x %= INF;
        x *= bin_pow(2, INF - 2);
        x %= INF;
        ans[i] += x;
        ans[i] %= INF;
        st.push({h[i], i});
    }
    // cout << "goida" << endl;
    for(int i = 1; i <= n; i++){
        cout << dp[i] << " ";
    }
    cout << ans[n] << endl;
}

Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:33:10: warning: variable 'flg' set but not used [-Wunused-but-set-variable]
   33 |     bool flg = 1;
      |          ^~~

• 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