Submission #288661

#	Time	Username	Problem	Language	Result	Execution time	Memory
288661		AMO5	Bigger segments (IZhO19_segments)	C++17	100 / 100	71 ms	16440 KiB

segments

//modified from errorgorn's solution
#include <bits/stdc++.h>

using namespace std;

#define ll long long 
#define sz(x) (int)x.size()
#define fi first
#define se second

const int mxn = 5e5+5;

int n,cnt[mxn];
ll a[mxn];

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	cin>>n;
	for(int i=1; i<=n; i++){
		cin>>a[i];
		a[i]+=a[i-1];
	}
	deque<pair<ll,int>>dq;
	dq.emplace_back(0ll,0);
	//expected sum , ind 
	for(int i=1; i<=n; i++){
		while(sz(dq)>=2&&dq[1].fi<=a[i])dq.pop_front();
		cnt[i]=cnt[dq.front().se]+1;
		pair<ll,int>cur=pair<ll,int>(2*a[i]-a[dq.front().se],i);
		while(dq.back().fi>=cur.fi)dq.pop_back();
		dq.emplace_back(cur);
	}
	cout<<cnt[n]<<"\n";
	return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27