Submission #910992

#	Time	Username	Problem	Language	Result	Execution time	Memory
910992		daoquanglinh2007	Bigger segments (IZhO19_segments)	C++17	0 / 100	2 ms	2396 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
 
const int NM = 5e5;
 
int N, a[NM+5], pref[NM+5], trace[NM+5];
pii dp[NM+5];
 
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];
	}
	dp[1] = mp(1, a[1]);
	trace[1] = 1;
	int t = 1;
	for (int i = 2; i <= N; i++){
		int l, r, j = -1;
		if (pref[i]-pref[t] >= dp[t].se) l = t+1, r = i;
		else{
			l = trace[i-1], r = t;
		}
		while (l <= r){
			int mid = (l+r)/2;
			if (pref[i]-pref[mid-1] >= dp[mid-1].se){
				j = mid;
				l = mid+1;
			}
			else r = mid-1;
		}
		dp[i].fi = dp[j-1].fi+1;
		dp[i].se = pref[i]-pref[j-1];
		trace[i] = j;
		if (dp[i].fi > dp[i-1].fi) t = i;
	}
	cout << dp[N].fi;
	return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |  freopen("SEGMENTS.inp", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
segments.cpp:17:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |  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