Submission #470010

#	Time	Username	Problem	Language	Result	Execution time	Memory
470010		Killer2501	Hacker (BOI15_hac)	C++14	100 / 100	221 ms	103116 KiB

hac

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define task "tests"
#define pll pair<ll, ll>
#define pi pair<ll, pll>
#define fi first
#define se second

using namespace std;
const ll mod = 1e9+7;
const ll N = 5e5+5;
const int base = 313;
ll n, m, t, k, T, ans, q, tong, c[N], a[N], b[N], h[N], P[N][21];
vector<ll> adj[N], kq;
ll pw(ll k, ll n)
{
    ll total = 1;
    for(; n; n >>= 1)
    {
        if(n & 1)total = total * k % mod;
        k = k * k % mod;
    }
    return total;
}
ll sum(ll l, ll r)
{
    if(l <= r)return b[r] - b[l-1];
    return b[r] + b[n] - b[l-1];
}
ll mx(ll l, ll r)
{
    ll log = log2(r-l+1);
    return max(P[l][log], P[r-(1<<log)+1][log]);
}
ll get(ll l, ll r)
{
    if(l <= r)return mx(l, r);
    return max(mx(1, r), mx(l, n));
}
void sol()
{
    cin >> n;
    for(int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        b[i] = b[i-1] + a[i];
    }
    for(int i = 1; i <= n; i ++)
    {
        int j = i + n/2 - 1;
        if(j > n)j -= n;
        P[i][0] = sum(i, j);
    }
    for(int j = 1; j <= 20; j ++)
    {
        for(int i = 1; i+(1<<j)-1 <= n; i ++)P[i][j] = max(P[i][j-1], P[i+(1<<(j-1))][j-1]);
    }
    for(int i = 1; i <= n; i ++)
    {
        int l = i + 1, r = i - n / 2;
        if(l > n)l -= n;
        if(r <= 0)r += n;
        ans = max(ans, b[n]- get(l, r));
    }
    cout << ans;
}
int main()
{
    if(fopen(task".in", "r"))
    {
       freopen(task".in", "r", stdin);
       freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:72:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |        freopen(task".in", "r", stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:73:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |        freopen(task".out", "w", stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40