Submission #676487

#	Time	Username	Problem	Language	Result	Execution time	Memory
676487		penguin133	Discharging (NOI20_discharging)	C++17	100 / 100	160 ms	33464 KiB

Discharging

#include <bits/stdc++.h>
using namespace std;
#define int long long
deque<pair<int, int> > dq;
int f(pair<int, int> x, int y){
	return x.first*y + x.second;
}
long double intersect(int a, int b, int c, int d){
	return (long double)(d-b)/(a-c);
}
void ins(int m , int c){
	while(dq.size() > 1){
		int s = dq.size();
		if(intersect(dq.back().first, dq.back().second,m,c) <= intersect(dq[s-2].first, dq[s-2].second, m,c))dq.pop_back();
		else break;
	}
	dq.push_back(make_pair(m,c));
} 

int query(int x){
	while(dq.size() > 1){
		if(f(dq[0], x) <= f(dq[1], x))dq.pop_front();
		// <= for max dp, >= for min dp
		else break;
	}
	return f(dq[0], x);
}
int dp[1000005], A[1000005];
int Pmax[1000005];
main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int n;cin >> n;
	for(int i=1;i<=n;i++){
		cin >> A[i];Pmax[i] = max(Pmax[i-1], A[i]);
	}
	dq.push_back(make_pair(0, 0));
	for(int i=1;i<=n;i++){
		int x = Pmax[i];
		dp[i] = x*n - query(x);
		ins(i, -dp[i]);
	}
	cout << dp[n];
}

Compilation message (stderr)

Discharging.cpp:30:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   30 | main(){
      | ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 25 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 28 / 28