Submission #627268

#	Time	Username	Problem	Language	Result	Execution time	Memory
627268		ngpin04	Bigger segments (IZhO19_segments)	C++17	100 / 100	455 ms	253068 KiB

segments

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define getbit(x, i) (x >> i) & 1
#define TASK ""
#define ALL(x) (x).begin(), (x).end() 
using namespace std;
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}
const int N = 5e5 + 5; 
const int oo = 1e9;
const long long ooo = 1e18;
const int mod = 1e9 + 7; // 998244353;
const long double pi = acos(-1);
 
pair <int, int> dp[N];
pair <int, int> val[50 * N];
 
long long s[N];
 
int ptr[50 * N][2];
int a[N];
int n,cnt;
 
void add(long long x, pair <int, int> v) {
	int cur = 0;
	for (int i = 49; i >= 0; i--) {
		int &p = ptr[cur][getbit(x, i)];
		if (!p)
			p = ++cnt;
		cur = p;
		maxi(val[cur], v);
	} 
}
 
pair <int, int> getmax(long long x) {
	int cur = 0;
	pair <int, int> res = mp(0, 0);
	for (int i = 49; i >= 0; i--) {
		int d = getbit(x, i);
		if (d == 1)
			maxi(res, val[ptr[cur][d ^ 1]]);
		cur = ptr[cur][d];
		if (cur == 0)
			break;
	}
	maxi(res, val[cur]);
	return res;
}
 
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef ONLINE_JUDGE
	// freopen(TASK".inp","r",stdin);
	// freopen(TASK".out","w",stdout);
	#endif
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		s[i] = s[i - 1] + a[i];
	}
 
	add(0, mp(0, 0));
	for (int i = 1; i <= n; i++) {
		long long tot = 0;
		pair <int, int> pir = getmax(s[i]);
		pir.fi++;
		dp[i] = pir;
		int j = pir.se;
 
		// cerr << i << " " << j << "\n";
 
		add(s[i] - s[j] + s[i], mp(dp[i].fi, i));
	}
 
	cout << dp[n].fi;
	return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:71:13: warning: unused variable 'tot' [-Wunused-variable]
   71 |   long long tot = 0;
      |             ^~~

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