Submission #723588

#	Time	Username	Problem	Language	Result	Execution time	Memory
723588		MDSPro	Hacker (BOI15_hac)	C++17	100 / 100	226 ms	8808 KiB

hac

#include "bits/stdc++.h"

using namespace std;
const int MAXN = 3e6;
const int INF = 1e9;

int n,N;
vector<int> tr;
void build(int n){
    N = (1<<(32-__builtin_clz(n)));
    tr.assign(2*N,INF);
}

void upd(int l, int r, int val){
    if(l >= n) upd(l-n,r-n,val);
    else if(r > n) {
        upd(l,n,val);
        upd(0,r-n,val);
    } else {
        for(l += N, r += N; l < r; l >>= 1, r >>= 1){
            if(l&1) {
                tr[l] = min(tr[l],val);
                l++;
            }

            if(r&1) {
                --r;
                tr[r] = min(tr[r],val);
            }
        }
    }
}

int get(int idx){
    int ans = INF;
    for(idx += N; idx > 0; idx >>= 1) ans = min(tr[idx],ans);
    return ans;
}

int main(){
    cin >> n;
    vector<int> v(2*n);
    for(int i = 0,x; i < n; ++i){
        cin >> x;
        v[i] = v[i+n] = x;
    }
    
    build(n);
    
    int sum = 0;
    int need = (n+1)/2;
    for(int i = 0; i < 2*n; ++i){
        sum += v[i];
        if(i-need+1 >= 0) {
            upd(i-need+1,i+1,sum);
            sum -= v[i-need+1];
        }
    }

    int res = 0;
    for(int i = 0; i < n; ++i) res = max(res,get(i));
    cout << res;
}

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