Submission #1090778

#	Time	Username	Problem	Language	Result	Execution time	Memory
1090778		ShaShi	Hacker (BOI15_hac)	C++17	100 / 100	95 ms	45904 KiB

hac

#include <bits/stdc++.h>
 
// #define int long long
 
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
 
#define F first 
#define S second
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define kill(x) cout << x << "\n", exit(0);
#define pii pair<int, int>
#define endl "\n"
 
 
 
using namespace std;
typedef long long ll;
// typedef __int128_t lll;
typedef long double ld;
 
const int MAXN = (int)1e6 + 7;
const int MOD = (int)1e9 + 7;
const int INF = (int)1e9 + 7;
const int LG = 20;
 
 
int n, m, k, tmp, t, tmp2, tmp3, tmp4, u, v, w, flag, q, ans, flag2;
int arr[MAXN], ps[MAXN], dp[MAXN];
int sps[MAXN][LG];


inline int go_fw(int ind, int k) {
    if (ind+k-1 <= n) return ps[ind+k-1]-ps[ind-1];
    return ps[n]-ps[ind-1]+go_fw(1, k-(n-ind+1));
}


inline int get_mn(int v, int k) {
    int res = INF;
    
    for (int i=LG-1; i>=0; i--) {
        if (k&(1<<i)) {
            res = min(res, sps[v][i]);
            v += (1<<i);
        }
    }

    return res;
}


inline int solve(int ind) {
    int j = ind, res = INF;

    if (ind >= (n+1)/2) return get_mn(ind-(n+1)/2+1, (n+1)/2);
    return min(get_mn(1, ind), get_mn(n-((n+1)/2-ind)+1, (n+1)/2-ind));
}
 
int32_t main() {
    #ifdef LOCAL
    freopen("inp.in", "r", stdin);
    freopen("res.out", "w", stdout);
    #else
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #endif

    cin >> n;

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

        ps[i] = ps[i-1]+arr[i];
    }

    for (int i=1; i<=n; i++) sps[i][0] = go_fw(i, (n+1)/2);
    for (int j=1; j<LG; j++) for (int i=1; i<=n; i++) sps[i][j] = min(sps[i][j-1], sps[i+(1<<(j-1))][j-1]);

    ans = 0;

    for (int i=1; i<=n; i++) ans = max(ans, solve(i));

    cout << ans << endl;
 
    return 0;
}

Compilation message (stderr)

hac.cpp: In function 'int solve(int)':
hac.cpp:57:9: warning: unused variable 'j' [-Wunused-variable]
   57 |     int j = ind, res = INF;
      |         ^
hac.cpp:57:18: warning: unused variable 'res' [-Wunused-variable]
   57 |     int j = ind, res = INF;
      |                  ^~~

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