Submission #671419

#	Time	Username	Problem	Language	Result	Execution time	Memory
671419		Alihan_8	Divide and conquer (IZhO14_divide)	C++17	100 / 100	33 ms	8044 KiB

divide

#include <bits/stdc++.h>
// include <ext/pb_ds/assoc_container.hpp>
// include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
using namespace std;
#define all(x) x.begin(), x.end()
#define pb push_back
// define ordered_set tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>
#define mpr make_pair
#define ln '\n'
void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
#define int long long
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n; cin >> n;
    vector <int> x(n), g(n), d(n);
    for ( int i = 0; i < n; i++ ) cin >> x[i] >> g[i] >> d[i];
    vector <int> pref_g(n), pref_d(n);
    for ( int i = 0; i < n; i++ ){
        pref_g[i] = (i ? pref_g[i-1] : 0)+g[i];
        pref_d[i] = (i ? pref_d[i-1] : 0)+d[i];
    }
    vector <int> val(n), suff(n, -1e18);
    for ( int i = 0; i < n; i++ ) val[i] = pref_d[i]-x[i];
    for ( int i = n-1; i >= 0; i-- ){
        if ( i+1 < n ) suff[i] = suff[i+1];
        suff[i] = max(suff[i], val[i]);
    }
    int Mx = 0;
    for ( int i = 0; i < n; i++ ){
        int l = i, r = n;
        while ( l+1 < r ){
            int md = (l+r)>>1;
            if ( suff[md]+x[i]-(i ? pref_d[i-1] : 0) < 0 ) r = md;
            else l = md;
        }
        Mx = max(Mx, pref_g[l]-(i ? pref_g[i-1] : 0));
    }
    cout << Mx;

    cout << '\n';
}

Compilation message (stderr)

divide.cpp: In function 'void IO(std::string)':
divide.cpp:11:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
divide.cpp:11:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 31 / 31
• Subtask 3: 52 / 52