Submission #1229138

#	Time	Username	Problem	Language	Result	Execution time	Memory
1229138		hungeazy	Fancy Fence (CEOI20_fancyfence)	C++20	55 / 100	15 ms	4168 KiB

fancyfence

/*
* @Author: hungeazy
* @Date:   2025-07-01 15:26:20
* @Last Modified by:   hungeazy
* @Last Modified time: 2025-07-01 16:16:41
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
// #pragma GCC optimize("O3")  
// #pragma GCC optimize("unroll-loops")  
// #pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")  
using namespace std;
using namespace __gnu_pbds; 
bool M1;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define int long long
#define ll long long 
#define ull unsigned long long
#define sz(x) x.size()
#define sqr(x) (1LL * (x) * (x))
#define all(x) x.begin(), x.end()
#define fill(f,x) memset(f,x,sizeof(f))
#define FOR(i,l,r) for(int i=l;i<=r;i++)
#define FOD(i,r,l) for(int i=r;i>=l;i--)
#define debug(x) cout << #x << " = " << x << '\n'
#define ii pair<int,int>
#define iii pair<int,ii>
#define di pair<ii,ii>
#define vi vector<int>
#define vii vector<ii>
#define mii map<int,int>
#define fi first
#define se second
#define pb push_back
#define MOD 1000000007
#define __lcm(a,b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define YES cout << "YES\n"
#define NO cout << "NO\n"
#define MASK(i) (1LL << (i))
#define c_bit(i) __builtin_popcountll(i)
#define BIT(x,i) ((x) & MASK(i))
#define SET_ON(x,i) ((x) | MASK(i))
#define SET_OFF(x,i) ((x) & ~MASK(i))
#define oo 1e18
#define name "RECT"
#define endl '\n'
#define memory() cerr << abs(&M2-&M1)/1024.0/1024 << " MB" << endl
#define time() cerr << endl << "-------------Time:" << 1000.0 * clock() / CLOCKS_PER_SEC << "ms." << endl
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
template <class T> using ordered_set = tree <T, null_type, less_equal <T>, rb_tree_tag,tree_order_statistics_node_update>;
const int N = (int)1e5+10;
int n,h[N],w[N];

namespace hungeazy {

	int pre[N],dp[N];

	int calc(int a, int b)
	{
		if (b == 0) return 1;
		if (b == 1) return a;
		int p = calc(a,b/2);
		p = sqr(p)%MOD;
		if (b&1) (p *= a) %= MOD;
		return p;
	}

	int inv2 = calc(2,MOD-2);

	int f(int x) {
		return x%MOD*(x+1)%MOD*inv2%MOD;
	}

	int mul(int a, int b) {
		return (a%MOD*b%MOD)%MOD;
	}

	void solve(void)
	{
		FOR(i,1,n) pre[i] = pre[i-1]+w[i];
		stack<int> s;
		s.push(0);
		int ans = 0;
		FOR(i,1,n)
		{
			while (!s.empty() and h[i] <= h[s.top()])
				s.pop();
			dp[i] = (dp[s.top()]+mul(f(h[i]),pre[i]-pre[s.top()]))%MOD;
			(ans += mul(dp[s.top()],w[i])+mul(f(h[i]),mul(pre[i-1]-pre[s.top()],w[i]))+mul(f(h[i]),f(w[i]))) %= MOD;
			s.push(i);
		}
		cout << ans;
	}
	
}

bool M2;
signed main()
{
    fast;
    if (fopen(name".inp","r"))
    {
    	freopen(name".inp","r",stdin);
    	freopen(name".out","w",stdout);
    }
    cin >> n;
    FOR(i,1,n) cin >> h[i];
    FOR(i,1,n) cin >> w[i];
    hungeazy::solve();
    time();
    memory();
    return 0;
}
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Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(name".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
fancyfence.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen(name".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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