Submission #201054

#	Time	Username	Problem	Language	Result	Execution time	Memory
201054		a1_N	Bigger segments (IZhO19_segments)	C++17	73 / 100	909 ms	262144 KiB

segments

#include <bits/stdc++.h>
#define F first
#define S second
using namespace std;
const int N = (int)5e5 + 5;
const long long M = (long long)6e14;
    
int n,timer = 1,a[N],L[N * 20],R[N * 20];
pair<int,int> t[N * 20];
long long pref[N];
pair<int,long long> dp[N];
pair<int,int> ZeroPair = {0,0};

void upd(int v,long long tl,long long tr,long long pos,pair<int,int> val){
	if(tl == tr){
		t[v] = val;
		return;
	}
	long long tm = (tl + tr) >> 1;
	if(pos <= tm){
		if(!L[v]) L[v] = ++timer;
		upd(L[v],tl,tm,pos,val);
	}
	else{
		if(!R[v]) R[v] = ++timer;
		upd(R[v],tm + 1,tr,pos,val);
	}
	t[v] = max(t[L[v]],t[R[v]]);
}

pair<int,int> get(int v,long long tl,long long tr,long long l,long long r){
	if(l <= tl && tr <= r) return t[v];
	if(tl > r || tr < l) return ZeroPair;
	long long tm = (tl + tr) >> 1;
	return max(get(L[v],tl,tm,l,r),get(R[v],tm + 1,tr,l,r));
}

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];
		pref[i] = pref[i - 1] + a[i];
	}
	dp[1] = {1,a[1]};
	upd(1,1,M,pref[1] + dp[1].S,make_pair(dp[1].F,1));
	for(int i = 2; i <= n; i++){
		dp[i] = {dp[i - 1].F,dp[i - 1].S + a[i]};
		pair<int,int> cur = get(1,1,M,1,pref[i]);
		if(cur.F > 0) dp[i] = {cur.F + 1,pref[i] - pref[cur.S]};
		upd(1,1,M,pref[i] + dp[i].S,make_pair(dp[i].F,i));	
	}
	cout << dp[n].F;
	return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 0 / 27