Submission #448250

#	Time	Username	Problem	Language	Result	Execution time	Memory
448250		JovanB	도넛 (JOI14_ho_t3)	C++17	100 / 100	79 ms	4468 KiB

2014_ho_t3

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef long double ld;
 
ll pre[200005];
 
int lp, rp;
 
ll ternary(int l, int r){
    if(r-l <= 3){
        ll mn = 1e18;
        for(int i=l; i<=r; i++){
            ll x = abs(pre[i]-pre[lp-1]-(pre[rp]-pre[i]));
            mn = min(mn, x);
        }
        return (pre[rp]-pre[lp-1]-mn)/2;
    }
    int a = l + (r-l)/3;
    int b = r - (r-l)/3;
    ll a1 = abs(pre[a]-pre[lp-1]-(pre[rp]-pre[a]));
    ll b1 = abs(pre[b]-pre[lp-1]-(pre[rp]-pre[b]));
    if(a1 == b1) return ternary(a, b);
    if(a1 < b1) return ternary(l, b);
    if(a1 > b1) return ternary(a, r);
}
 
ll a[200005];
 
int main(){
    ios_base::sync_with_stdio(false), cin.tie(0);
    cout.precision(10);
    cout << fixed;
 
    int n;
    cin >> n;
    for(int i=1; i<=n; i++){
        cin >> a[i];
        a[i+n] = a[i];
    }
    for(int i=1; i<=2*n; i++){
        pre[i] = pre[i-1]+a[i];
    }
    int r = 1;
    ll res = 0;
    for(int l=1; l<=n; l++){
        lp = r+1;
        rp = l+n-1;
        while(ternary(r+1, l+n-1) >= pre[r]-pre[l-1]){
            res = max(res, pre[r]-pre[l-1]);
            r++;
            lp = r+1;
            rp = l+n-1;
        }
    }
    cout << res << "\n";
    return 0;
}

Compilation message (stderr)

2014_ho_t3.cpp: In function 'll ternary(int, int)':
2014_ho_t3.cpp:27:1: warning: control reaches end of non-void function [-Wreturn-type]
   27 | }
      | ^

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 30 / 30
• Subtask 4: 50 / 50