Submission #1167848

#	Time	Username	Problem	Language	Result	Execution time	Memory
1167848		SmuggingSpun	Divide and conquer (IZhO14_divide)	C++20	100 / 100	22 ms	3912 KiB

divide

#include<bits/stdc++.h>
#define taskname "A"
using namespace std;
typedef long long ll;
const int lim = 1e5 + 5;
const ll INF = 1e18;
template<class T>void minimize(T& a, T b){
    if(a > b){
        a = b;
    }
}
template<class T>void maximize(T& a, T b){
    if(a < b){
        a = b;
    }
}
struct Data{
    int x, g, d;
    bool operator <(const Data& other){
        return this->x < other.x;
    }
};
int n;
Data a[lim];
namespace sub12{
    void solve(){
        ll ans = 0;
        for(int i = 1; i <= n; i++){
            ll gold = 0, energy = 0;
            for(int j = i; j <= n; j++){
                gold += a[j].g;
                if((energy += a[j].d) >= a[j].x - a[i].x){
                    maximize(ans, gold);
                }
            }
        }
        cout << ans;
    }
}
namespace sub3{
    ll fe[lim], fg[lim];
    void solve(){
        ll ans = fe[0] = fg[0] = 0;
        vector<int>l(n), r(n);
        for(int i = 1; i <= n; i++){
            fe[l[i - 1] = r[i - 1] = i] = fe[i - 1] + a[i].d;
            fg[i] = fg[i - 1] + a[i].g;
        }
        sort(l.begin(), l.end(), [&] (int i, int j){
            return fe[i] - a[i].x < fe[j] - a[j].x;
        });
        sort(r.begin(), r.end(), [&] (int i, int j){
            return fe[i - 1] - a[i].x < fe[j - 1] - a[j].x;
        });
        int j = 0;
        ll min_gold = INF;
        for(int& i : l){
            while(j < n && fe[r[j] - 1] - a[r[j]].x <= fe[i] - a[i].x){
                minimize(min_gold, fg[r[j++] - 1]);
            }
            maximize(ans, fg[i] - min_gold);
        }
        cout << ans;
    }
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
    cin >> n;
    for(int i = 1; i <= n; i++){
        cin >> a[i].x >> a[i].g >> a[i].d;
    }
    sort(a + 1, a + n + 1);
    if(n <= 5000){
        sub12::solve();
    }
    else{
        sub3::solve();
    }
}

Compilation message (stderr)

divide.cpp: In function 'int main()':
divide.cpp:69:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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