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 <bits/stdc++.h>
using namespace std;
using i64 = long long;
const int MAXN = 5e5 + 5;
using pli = pair<i64, int>;
const i64 oo64 = 5e14 + 5;
#define left ___left
#define right ___right
struct node {
pli x = {0, 0};
node *left = nullptr, *right = nullptr;
node(pli x = {0, 0}, node *left = nullptr, node *right = nullptr) : x(x), left(left), right(right) {}
};
pli combine(const pli a, const pli b) {
if(a.second > b.second)
return a;
if(a.second < b.second)
return b;
return {max(a.first, b.first), a.second};
}
struct segment_tree {
node *root = new node();
void update(node *cur, i64 l, i64 r, i64 p, pli x) {
if(r < p or l > p) return;
if(l == r) {
cur -> x = combine(cur -> x, x);
return;
}
i64 m = (l + r) / 2;
if(p <= m) {
if(cur -> left == nullptr) cur -> left = new node();
update(cur -> left, l, m, p, x);
} else {
if(cur -> right == nullptr) cur -> right = new node();
update(cur -> right, m + 1, r, p, x);
}
cur -> x = {0, 0};
if(cur -> left != nullptr)
cur -> x = combine(cur -> x, cur -> left -> x);
if(cur -> right != nullptr)
cur -> x = combine(cur -> x, cur -> right -> x);
}
pli get(node *cur, i64 l, i64 r, i64 u, i64 v) {
if(r < u or l > v) return {0, 0};
if(u <= l and r <= v) return cur -> x;
i64 m = (l + r) / 2;
pli res = {0, 0};
if(cur -> left != nullptr)
res = combine(res, get(cur -> left, l, m, u, v));
if(cur -> right != nullptr)
res = combine(res, get(cur -> right, m + 1, r, u, v));
return res;
}
void update(i64 p, pli x) {
return update(root, 1, oo64, p, x);
}
pli get(i64 l, i64 r) {
return get(root, 1, oo64, l, r);
}
} ST;
int N;
int a[MAXN];
i64 b[MAXN];
pli dp[MAXN];
signed main() {
#define TASK "code"
if (fopen(TASK ".inp", "r")) {
freopen(TASK ".inp", "r", stdin);
freopen(TASK ".out", "w", stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N;
for(int i = 1; i <= N; i++) cin >> a[i];
for(int i = 1; i <= N; i++) b[i] = b[i - 1] + a[i];
ST.update(0, {0, 0});
for(int i = 1; i <= N; i++) {
pli res = ST.get(0, b[i]);
dp[i] = {b[i] - res.first, res.second + 1};
ST.update(dp[i].first + b[i], {b[i], dp[i].second});
}
cout << dp[N].second;
return (0 ^ 0);
}
/**
4
2 3 1 7
**/
/**
5
6 2 3 9 13
**/
/**
3
3 1 2
**/
Compilation message (stderr)
segments.cpp: In function 'int main()':
segments.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
82 | freopen(TASK ".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
83 | freopen(TASK ".out", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
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