Submission #343994

#	Time	Username	Problem	Language	Result	Execution time	Memory
343994		IZhO_2021_I_want_Silver	Bigger segments (IZhO19_segments)	C++14	37 / 100	1566 ms	5100 KiB

segments

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,sse3,sse4,popcnt,abm,mmx")

#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <iomanip>
#include <cassert>
#include <stack>
#include <queue>
#include <deque>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>-

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

// template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//  order_of_key (k) : Number of items strictly smaller than k .
//  find_by_order(k) : K-th element in a set (counting from zero).
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define pb push_back
#define ppb pop_back
#define mkp make_pair
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define show(a) cerr << #a <<" -> "<< a <<" "
#define nl cerr <<"\n"
#define int ll

const int N = 5e5 + 5;
const int oo = 1e15 + 5;

int n, a[N], sum[N], dp[N][2], ans, mn[N];

void solve() {
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        sum[i] = sum[i-1] + a[i];
    }
    for (int i = 1; i <= n; ++i) {
        dp[i][1] = sum[i];
    }
    mn[n+1] = oo;
    for (int i = n; i >= 1; --i) {
        mn[i] = min(mn[i+1], dp[i][1] + sum[i]);
    }
    int ans = 1;
    for (int k = 2; k <= n; ++k) {
        for (int i = 1; i <= n; ++i) {
            dp[i][(k & 1)] = oo;
            int l = 1, r = i-1;
            while (l < r) {
                int mid = (l + r + 1) / 2;
                if (mn[mid] <= sum[i]) l = mid;
                else r = mid - 1;
            }
            if (mn[l] <= sum[i]) { dp[i][(k & 1)] = min(dp[i][(k & 1)], sum[i] - sum[l]); }
        }
        for (int i = n; i >= 1; --i) {
            mn[i] = min(mn[i+1], dp[i][(k & 1)] + sum[i]);
            if (dp[n][(k & 1)] != oo) { ans = k; }
        }
        if (ans < k) { break; }
    }
    cout << ans;
}

 main () {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int tests = 1;
	//cin >> tests;
	while (tests --) {
		solve();
	}
	return 0;
}
/*
    Just Chalish!
*/

Compilation message (stderr)

segments.cpp:80:8: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   80 |  main () {
      |        ^

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