Submission #1215859

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215859		Madhav_1608	Hacker (BOI15_hac)	C++20	100 / 100	38 ms	17992 KiB

hac

#include <iostream>
#include <stack>
#include <queue>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <climits>
#include <cmath>
#include <unordered_map>
#include <unordered_set>
#include <numeric>
#include <iomanip>
#include <cstring>
#include <stdio.h>
#include <assert.h>
#include <complex>
#include <array>
#include <utility>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<long long> vll;
typedef pair<ll,ll> pll;
#define double long double
#define F first
#define S second
const double eps = 1e-12; 
#define FOR(i,a,b) for(long long i=a;i<b;i++)
#define all(v) v.begin(),v.end()
template <typename I>
void print(vector<I> &v){
    FOR(i,0,v.size()){cout << v[i] << " ";}
    cout << "\n";
}
ll gcd(ll a,ll b){
    if(a==0){return b;}
    else if(b==0){return a;}
    else if(a<b){return gcd(b%a,a);}
    else{return gcd(a%b,b);}
}
ll lcm(ll a,ll b){
    return (a/gcd(a,b))*b;
}
void setIO(string name = "") {
    freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
    freopen((name + ".out").c_str(), "w", stdout);
}
void init_code(){
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
}
void solve(){
    // store very big numbers may mean log2.
    // A comparator must return false for two equal objects. Not doing so results in undefined behavior.
    ll n;
    cin >> n;
    vll a(2*n);
    FOR(i,0,n) cin >> a[i];
    vll prefix(2*n+1,0);
    FOR(i,0,n){
        a[i+n] = a[i];
    }
    FOR(i,0,2*n){
        prefix[i+1] = prefix[i]+a[i];
    }
    deque<ll> d;
    ll sz = n/2;
    ll ans = INT_MAX;
    ll curr;
    FOR(i,sz,n){
        curr = prefix[i]-prefix[i-sz];
        while((!d.empty())&&(d.back()<curr)) d.pop_back();
        d.push_back(curr);
    }
    FOR(i,n,2*n+1){
        ans = min(ans,d.front());
        curr = prefix[i]-prefix[i-sz];
        while((!d.empty())&&(d.back()<curr)) d.pop_back();
        d.push_back(curr);
        curr = prefix[i-n+sz]-prefix[i-n];
        if(d.front()==curr) d.pop_front();
    }
    ll sumi = 0;
    FOR(i,0,n) sumi+=a[i];
    cout << (sumi-ans) << "\n";
}

signed main(){
    //setIO
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // init_code();
    ll t=1;
    // cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

Compilation message (stderr)

hac.cpp: In function 'void setIO(std::string)':
hac.cpp:48:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |     freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:49:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |     freopen((name + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp: In function 'void init_code()':
hac.cpp:53:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |     freopen("input.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:54:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |     freopen("output.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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