Submission #911019

#	Time	Username	Problem	Language	Result	Execution time	Memory
911019		daoquanglinh2007	Bigger segments (IZhO19_segments)	C++17	0 / 100	2 ms	344 KiB

segments

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair
#define isz(a) (int)(a).size()
 
const int NM = 5e5;
 
int N, a[NM+5], pref[NM+5], trace[NM+5];
pii dp[NM+5];
vector <int> v;

void add(int x){
	while (!v.empty() && pref[v.back()]+dp[v.back()].se >= pref[x]+dp[x].se) v.pop_back();
	v.push_back(x);
}
 
signed main(){
	freopen("SEGMENTS.inp", "r", stdin);
	freopen("SEGMENTS.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];
		pref[i] = pref[i-1]+a[i];
	}
	add(0);
	for (int i = 1; i <= N; i++){
		int l = 0, r = isz(v)-1;
		while (l <= r){
			int mid = (l+r)/2;
			if (pref[i] >= pref[v[mid]]+dp[v[mid]].se){
				dp[i].fi = dp[v[mid]].fi+1;
				dp[i].se = pref[i]-pref[v[mid]];
				l = mid+1;
			}
			else r = mid-1;
		}
		add(i);
	}
	cout << dp[N].fi;
	return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:23:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |  freopen("SEGMENTS.inp", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:24:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |  freopen("SEGMENTS.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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