Submission #1160241

#	Time	Username	Problem	Language	Result	Execution time	Memory
1160241		akniet0	Bigger segments (IZhO19_segments)	C++20	27 / 100	3 ms	528 KiB

segments

#pragma GCC optimize(2)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline","fast-math","unroll-loops","no-stack-protector")
#pragma GCC diagnostic error "-fwhole-program"
#pragma GCC diagnostic error "-fcse-skip-blocks"
#pragma GCC diagnostic error "-funsafe-loop-optimizations"

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define ordered_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
#define len(x) (int)x.size()
#define ull unsigned long long
#define F first
#define S second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define int long long
#define ld long double
#define pii pair<int,int>
#define mii map<int,int>

using namespace std;
using namespace __gnu_pbds;
using ll = long long;

const int N = 5e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = 1e18;
const ll inf = 1e9;

struct str{
	int x,sum;
} dp[N];

int n,a[N],p[N];

signed main(){
	// freopen("txt.in", "r", stdin);
	// freopen("txt.out", "w", stdout);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	for (int i=1;i<=n;i++){
		cin >> a[i];
		p[i] = p[i-1] + a[i];
	}
	dp[1].x = 1;
	dp[1].sum = a[1];
	for (int i=1;i<=n;i++){
		if (!dp[i].x){
			int s = a[i];
			for (int j=i-1;j>=1;j--){
				if (s >= dp[j].sum && dp[j].x + 1 > dp[i].x){
					dp[i].x = dp[j].x + 1;
					dp[i].sum = s;
				}
				s+=a[j];
			}
			if (!dp[i].x){
				dp[i].x = dp[i-1].x;
				dp[i].sum = dp[i-1].sum + a[i];
			}
		}
		int l = i + 1;
		int r = n;
		while(l<=r){
			int md = (l + r) / 2;
			if (p[md] - p[i] < dp[i].sum){
				l = md + 1;
			}
			else{
				r = md - 1;
			}
		}
		// cout << i << ' ' << l << '\n';
		if (l <= n){
			if (dp[i].x + 1 >= dp[l].x){
				dp[l].sum = p[l] - p[i];
				dp[l].x = dp[i].x + 1;
			}
		}
	}
	cout << dp[n].x;
}

//order_of_key(k): Number of items strictly smaller than k .
//find_by_order(k): K-th element in a set (counting from zero).

//sum of squares n*(n+1)*(2n+1)/6
//sum of cubes [n*(n+1)/2]^2
//sum of squares for odds n*(4*n*n-1)/3
//sum of cubes for odds n*n*(2*n*n-1)

//a/b%mod = a*(b^(m-2)%mod)
//(a>>x)&1 == 0
//a^b = (a+b)-2(a&b)

//srand(time(0))-always changing

Compilation message (stderr)

segments.cpp:4:30: warning: '-fwhole-program' is not an option that controls warnings [-Wpragmas]
    4 | #pragma GCC diagnostic error "-fwhole-program"
      |                              ^~~~~~~~~~~~~~~~~
segments.cpp:5:30: warning: '-fcse-skip-blocks' is not an option that controls warnings [-Wpragmas]
    5 | #pragma GCC diagnostic error "-fcse-skip-blocks"
      |                              ^~~~~~~~~~~~~~~~~~~
segments.cpp:6:30: warning: '-funsafe-loop-optimizations' is not an option that controls warnings [-Wpragmas]
    6 | #pragma GCC diagnostic error "-funsafe-loop-optimizations"
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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