Submission #876234

#	Time	Username	Problem	Language	Result	Execution time	Memory
876234		Huy	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	56 ms	11996 KiB

fancyfence

#include<bits/stdc++.h>
#define int long long
#define pii pair<ll,ll>
#define fi first
#define se second
#pragma GCC tarGet ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC tarGet("avx,avx2,fma")
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ldb = long double;
const int N = 1e5;
const int maxN = 2e5 + 1;
const ll mod = 1e9 + 7;
const int block_size = 708;
const ll infty = 1e18;
const double ep = 1e-7;
const int base = 200003;

void InputFile()
{
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    freopen("test.out","r",stdin);
}

int n;
int h[maxN];
int w[maxN];
int prew[maxN];
int id[maxN];
int L[maxN];
int R[maxN];

bool FA(int i,int j)
{
    return (h[i] < h[j]) || (h[i] == h[j] && L[i] < L[j]);
}

ll power(int a,int b)
{
    if(b == 0) return 1;
    ll t = power(a,b/2);
    if(b % 2)
    {
        return t * t % mod * a % mod;
    }
    return t * t % mod;
}

ll C2(ll w)
{
    return (w % mod * ((w + 1) % mod) % mod * power(2,mod-2) % mod );
}

void Read()
{
    cin >> n;
    for(int i = 1; i <= n; i++)
    {
        cin >> h[i];
        id[i] = i;
    }
    for(int i = 1; i <= n; i++)
    {
        cin >> w[i];
        prew[i] = prew[i-1] + w[i];
    }

    vector<int> vc;
    for(int i = 1; i <= n; i++)
    {
        while(!vc.empty() && h[vc.back()] >= h[i])
        {
            vc.pop_back();
        }
        if(vc.empty()) L[i] = 0;
        else L[i] = vc.back();
        vc.push_back(i);
    }
    vc.clear();
    for(int i = n; i >= 1; i--)
    {
        while(!vc.empty() && h[vc.back()] >= h[i])
        {
            vc.pop_back();
        }
        if(vc.empty()) R[i] = n + 1;
        else R[i] = vc.back();
        vc.push_back(i);
    }

    sort(id + 1,id + n + 1,FA);
    ll res = 0;
    for(int i = 1; i <= n; i++)
    {
        if(h[id[i]] == h[id[i-1]] && L[id[i]] == L[id[i-1]]) continue;
        //cout << id[i] <<' ';
        ll need_w = prew[R[id[i]]-1] - prew[L[id[i]]];
        ll pp = max(h[L[id[i]]],h[R[id[i]]]);
        ll thua = h[id[i]] - pp;
        ll add = (C2(thua) + thua * pp % mod) % mod * C2(need_w) % mod ;
        res = (res + add) % mod;
    }
    cout << res;
    //cout << C2(3);
}

void Solve()
{

}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    //InputFile();
    //int sub_type;
    //cin >> sub_type;
    //Sieve();
    int test;
    //cin >> test;
    test = 1;
    while(test--)
        //for(int prc = 1; prc <= test; prc++)
    {
        Read();
        Solve();
        //Debug();
    }
}

Compilation message (stderr)

fancyfence.cpp:6: warning: ignoring '#pragma GCC tarGet' [-Wunknown-pragmas]
    6 | #pragma GCC tarGet ("avx2")
      | 
fancyfence.cpp:7: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    7 | #pragma GCC optimization ("O3")
      | 
fancyfence.cpp:8: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    8 | #pragma GCC optimization ("unroll-loops")
      | 
fancyfence.cpp:10: warning: ignoring '#pragma GCC tarGet' [-Wunknown-pragmas]
   10 | #pragma GCC tarGet("avx,avx2,fma")
      | 
fancyfence.cpp: In function 'void InputFile()':
fancyfence.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen("test.out","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• 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