#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)
template <class X, class Y>
inline bool maximize(X &x, Y y) {
return (x < y ? x = y, true : false);
}
template <class X, class Y>
inline bool minimize(X &x, Y y) {
return (x > y ? x = y, true : false);
}
template <class X>
inline void compress(vector<X> &a) {
sort(all(a));
a.resize(unique(all(a)) - a.begin());
}
int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
return l + abs((ll) rng()) % (r - l + 1);
}
const ll oo = (ll) 1e17;
const int inf = (ll) 1e9 + 7, mod = (ll) 1e9 + 7;
const int N = 6e5 + 5, M = 2e5 + 5, BASE = 307, LOG = 23;
void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }
int n;
int a[N];
pair<ll, ll> f[N];
const ll L = 0, R = 1e16;
struct dynamic {
struct node {
int value;
int lc, rc;
node() {
value = 0;
lc = rc = -1;
}
};
vector<node> st;
dynamic() { st.reverse(5e6); create(); }
void create() { st.pb(node()); }
void fix(int i) {
if (st[i].lc == -1) {
create();
st[i].lc = sz(st) - 1;
}
if (st[i].rc == -1) {
create();
st[i].rc = sz(st) - 1;
}
}
void upd(int i, ll l, ll r, ll p, int val) {
if (l > p || r < p) return;
if (l == r) {
maximize(st[i].value, val);
return;
}
fix(i);
ll m = (l + r) >> 1;
upd(st[i].lc, l, m, p, val);
upd(st[i].rc, m + 1, r, p, val);
st[i].value = max(st[ st[i].lc ].value, st[ st[i].rc ].value);
}
void upd(ll p, int val) {
return upd(0, L, R, p, val);
}
int get(int i, ll l, ll r, ll u, ll v) {
if (i == -1) return 0;
if (l > v || r < u) return 0;
if (l >= u && r <= v) return st[i].value;
fix(i);
ll m = (l + r) >> 1;
return max(get(st[i].lc, l, m, u, v), get(st[i].rc, m + 1, r, u, v));
}
int get(ll u, ll v) { return get(0, L, R, u, v); }
};
ll pf[N];
int main(void) {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n;
rep(i, n) cin >> a[i];
rep(i, n) pf[i] = pf[i - 1] + a[i];
dynamic dn;
forn(i, 1, n) {
int pos = dn.get(0, pf[i]);
f[i] = {f[pos].first + 1, pf[i] - pf[pos]};
dn.upd(f[i].second + pf[i], i);
}
cout << f[n].first;
return 0;
}
Compilation message
segments.cpp: In constructor 'dynamic::dynamic()':
segments.cpp:69:20: error: 'class std::vector<dynamic::node>' has no member named 'reverse'; did you mean 'reserve'?
69 | dynamic() { st.reverse(5e6); create(); }
| ^~~~~~~
| reserve
