Submission #870498

#	Time	Username	Problem	Language	Result	Execution time	Memory
870498		KiaRez	Bigger segments (IZhO19_segments)	C++17	100 / 100	115 ms	32672 KiB

segments

/*
    IN THE NAME OF GOD
*/
#include <bits/stdc++.h>

// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

using namespace std;

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

#define F                                      first
#define S                                      second
#define Mp                                     make_pair
#define pb                                     push_back
#define pf                                     push_front
#define size(x)                                ((ll)x.size())
#define all(x)                                 (x).begin(),(x).end()
#define kill(x)		                           cout << x << '\n', exit(0);
#define fuck(x)                                cout << "(" << #x << " , " << x << ")" << endl
#define endl                                   '\n'

const int N = 5e5+23, lg = 19;
ll Mod = 1e9+7; //998244353;

inline ll MOD(ll a, ll mod=Mod) {a%=mod; (a<0)&&(a+=mod); return a;}
inline ll poww(ll a, ll b, ll mod=Mod) {
    ll ans = 1;
    a=MOD(a, mod);
    while (b) {
        if (b & 1) ans = MOD(ans*a, mod);
        b >>= 1;
        a = MOD(a*a, mod);
    }
    return ans;
}

ll t, n, a[N], dp[N], pd[N], seg[4*N];

void update(int ind, ll val) {
	if(ind == 0) return;
	if(ind >= (1<<lg)) {
		seg[ind] = val;
	} else {
		seg[ind] = min(seg[2*ind], seg[2*ind+1]);
	}
	update(ind/2, val);
}

ll query(ll val, int ind=1) {
	if(ind >= (1<<lg)) {
		return (ind - (1<<lg) + 1);
	}
	if(seg[2*ind+1] <= val) return query(val, 2*ind+1);
	return query(val, 2*ind);
}

int main () {
	ios_base::sync_with_stdio(false), cin.tie(0);

	cin>>n;
	for(int i=1; i<=n; i++) {
		cin>>a[i];
		a[i] += a[i-1];
	}
	fill(seg, seg+4*N, (ll)1e18);

	update((1<<lg), 0);
	
	for(int i=1; i<=n; i++) {
		ll x = query(a[i]) - 1;
		dp[i] = a[i] - a[x], pd[i] = pd[x] + 1;
		update(i+(1<<lg), dp[i]+a[i]);
	}

	cout<<pd[n]<<endl;

	return 0;
}

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