Submission #365298

#	Time	Username	Problem	Language	Result	Execution time	Memory
365298		saleh	Split the sequence (APIO14_sequence)	C++17	71 / 100	2077 ms	9364 KiB

sequence

#pragma GCC optimize("unroll-loops,no-stack-protector,Ofast")
#include <bits/stdc++.h>
 
 
using namespace std;
 
 
const int MAXN = 100 * 1000 + 2, MAXK = 200 + 2;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
int n, k, chi, lvl;
int par[MAXK][MAXN];
long long dp[2 + 2][MAXN], ps[MAXN];
 
void cal(int l = chi, int r = n + 1, int ll = chi, int rr = n) {
	int mid = ((l + r) >> 1), md;
	for (int i = ll; i < mid && i < r; i++) if (dp[1 - lvl][i] + ps[i] * (ps[mid] - ps[i]) > dp[lvl][mid]) {
		dp[lvl][mid] = dp[1 - lvl][i] + ps[i] * (ps[mid] - ps[i]);
		md = i;
	}
	par[chi][mid] = md;
	if (l < mid) cal(l, mid, ll, md);
	if (mid + 1 < r) cal(mid + 1, r, md, rr);
}
 
 
 
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	cin >> n >> k;
	int a;
	for (int i = 0; i < n; i++) {
		cin >> a;
		ps[i + 1] = ps[i] + a;
	}
	for (int i = 1; i <= k; i++) {
		chi = i;
		lvl = i & 1;
		for (int j = i; j <= n; j++) dp[lvl][j] = -1;
		cal();
	}
	cout << dp[k & 1][n] << '\n';
	while (k > 0) {
		cout << par[k][n] << ' ';
		n = par[k][n];
		k--;
	}
	return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'void cal(int, int, int, int)':
sequence.cpp:36:18: warning: 'md' may be used uninitialized in this function [-Wmaybe-uninitialized]
   36 |  if (l < mid) cal(l, mid, ll, md);
      |               ~~~^~~~~~~~~~~~~~~~
sequence.cpp: In function 'int main()':
sequence.cpp:35:16: warning: 'md' may be used uninitialized in this function [-Wmaybe-uninitialized]
   35 |  par[chi][mid] = md;
      |  ~~~~~~~~~~~~~~^~~~
sequence.cpp:30:28: note: 'md' was declared here
   30 |  int mid = ((l + r) >> 1), md;
      |                            ^~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29