Submission #173558

#	Time	Username	Problem	Language	Result	Execution time	Memory
173558		Just_Solve_The_Problem	Bigger segments (IZhO19_segments)	C++11	100 / 100	146 ms	10372 KiB

segments

#include <bits/stdc++.h>

#define ll long long

using namespace std;          

const int N = (int)5e5 + 7;

int n;
int a[N], dp[N], ind[N];
ll pref[N];

main() {
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a[i]);
		pref[i] = pref[i - 1] + a[i];
	}
	for (int i = 1; i <= n; i++) {
		ind[i] = max(ind[i], ind[i - 1]);
		dp[i] = dp[ind[i]] + 1;
		int l = i;
		int r = n + 1;
		ll X = pref[i] * 2 - pref[ind[i]];
		while (r - l > 1) {
			int mid = (r + l) >> 1;
			if (X <= pref[mid]) {
				r = mid;
			} else {
				l = mid;
			}
		}
		ind[r] = i;
	}
	cout << dp[n];
}

Compilation message (stderr)

segments.cpp:13:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
segments.cpp: In function 'int main()':
segments.cpp:14:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
segments.cpp:16:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~

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