This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
void chmax(pair<ll, ll> &a, pair<ll, ll> b){
if(a.first < b.first){
a = b;
}else if(a.first == b.first){
if(a.second > b.second){
a = b;
}
}
}
struct normalize{
vector<ll> poi, pot;
void add(ll x){
poi.push_back(x);
}
void start(){
sort(poi.begin(), poi.end());
if(poi.size() > 0) pot.push_back(poi[0]);
for(int i = 1; i < (int)poi.size(); i++){
if(poi[i] != poi[i-1]){
pot.push_back(poi[i]);
}
}
}
int encode(ll x){
return lower_bound(pot.begin(), pot.end(), x) - pot.begin()+1;
}
};
struct ImplicitSegmentTree{
struct Node{
pair<ll, ll> v = {-INF, 0};
int ln = 0, rn = 0;
};
ll n, N;
vector<Node> T;
int cnt;
ImplicitSegmentTree(ll n): n(n){
N = n;
T.push_back(Node());
T.push_back(Node());
cnt = 1;
};
int new_node(){
T.push_back(Node());
cnt++;
return cnt;
}
void down(int node, ll low, ll high){
}
void apply(ll i, pair<ll, ll> x){
auto apply = [&](auto apply, int node, ll low, ll high, ll i, pair<ll, ll> x) -> void{
down(node, low, high);
if(low == high){
chmax(T[node].v, x);
down(node, low, high);
return;
}
ll mid = (low+high)/2;
if(i <= mid){
if(T[node].ln == 0){
int x = new_node();
T[node].ln = x;
}
apply(apply, T[node].ln, low, mid, i, x);
}else{
if(T[node].rn == 0){
int x = new_node();
T[node].rn = x;
}
apply(apply, T[node].rn, mid+1, high, i, x);
}
chmax(T[node].v, T[T[node].ln].v);
chmax(T[node].v, T[T[node].rn].v);
};
apply(apply, 1, 0, N, i, x);
}
pair<ll, ll> get(ll l, ll r){
auto get = [&](auto self, int node, ll low, ll high, ll l, ll r) -> pair<ll, ll>{
down(node, low, high);
if(low > r || l > high) return {-INF, 0};
if(low >= l && r >= high){
return T[node].v;
}
ll mid = (low+high)/2;
if(T[node].ln == 0){
int x = new_node();
T[node].ln = x;
}
if(T[node].rn == 0){
int x = new_node();
T[node].rn = x;
}
pair<ll, ll> res = {-INF, 0};
chmax(res, self(self, T[node].ln, low, mid, l, r));
chmax(res, self(self, T[node].rn, mid+1, high, l, r));
chmax(T[node].v, T[T[node].ln].v);
chmax(T[node].v, T[T[node].rn].v);
return res;
};
return get(get, 1, 0, N, l, r);
}
};
void solve(){
int n;
cin >> n;
vector<ll> a(n+1);
for(int i = 1; i <= n; i++){
cin >> a[i];
}
vector<ll> pf(n+1, 0);
for(int i = 1; i <= n; i++){
pf[i] = pf[i-1]+a[i];
}
auto sum = [&](int l, int r) -> ll{
return pf[r]-pf[l-1];
};
vector<pair<ll, ll>> f(n+1, {-INF, 0});
f[0] = {0, 0};
ImplicitSegmentTree T(2e14);
T.apply(0, {0, 0});
for(int i = 1; i <= n; i++){
f[i] = T.get(0, pf[i]);
f[i].first++;
f[i].second += pf[i];
T.apply(pf[i]+f[i].second, {f[i].first, -pf[i]});
}
cout << f[n].first;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen("main.inp", "r", stdin);
//freopen("main.out", "w", stdout);
solve();
}
Compilation message (stderr)
segments.cpp: In function 'void solve()':
segments.cpp:119:10: warning: variable 'sum' set but not used [-Wunused-but-set-variable]
119 | auto sum = [&](int l, int r) -> ll{
| ^~~
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