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Submission #625216

# Submission time Handle Problem Language Result Execution time Memory
625216 2022-08-09T16:12:47 Z IvanJ Split the sequence (APIO14_sequence) C++17
0 / 100
 67 ms 86688 KB 
#include<bits/stdc++.h>

#define x first
#define y second
#define pb push_back
#define all(a) (a).begin(), (a).end()

using namespace std;

typedef long long ll;
typedef pair<int, int> ii;

const int maxn = 1e5 + 5;
const double inf = 1e18, eps = 1e-9;

struct line {double a, b, p, idx;};

int n, k;
int A[maxn];
double pref[maxn];
double dp[maxn], dp1[maxn];
int opt[maxn][205];
vector<line> lines;

double getX(double a1, double b1, double a2, double b2) {
	return (b1 - b2) / (a2 - a1);	
}

void addLine(double a, double b, double idx) {
	double p = -inf;
	while(lines.size()) {
		p = getX(a, b, lines.back().a, lines.back().b);
		if(p < lines.back().p - eps) lines.pop_back();
		else break;
	}
	lines.pb({a, b, p, idx});
}

pair<double, int> getAns(double x) {
	int lo = 0, hi = (int)lines.size() - 1, ans = 0;
	while(lo <= hi) {
		int mid = (lo + hi) / 2;
		if(lines[mid].p <= x + eps) ans = mid, lo = mid + 1;
		else hi = mid - 1;
	}
	return {lines[ans].a * x + lines[ans].b, (int)lines[ans].idx};
}

int main() {
	scanf("%d%d", &n, &k);
	for(int i = 0;i < n;i++) scanf("%d", A + i);
	
	pref[0] = A[0];
	for(int i = 1;i < n;i++) pref[i] = pref[i - 1] + A[i];
	
	double ans = 0;
	for(int i = 1;i < k + 1;i++) {
		addLine(pref[i - 1], dp[i - 1] - pref[i - 1] * pref[i - 1], i - 1);
		for(int j = i;j < n;j++) {
			pair<double, int> p = getAns(pref[j]);
			dp1[j] = p.x;
			opt[j][i] = p.y;
			addLine(pref[j], dp[j] - pref[j] * pref[j], j);
		}
		for(int j = i;j < n;j++) dp[j] = dp1[j];
		ans = dp[n - 1];
		lines.clear();
	}
	printf("%d\n", (int)ans);
	int pos = n - 1;
	for(int i = k;i >= 1;i--) 
		printf("%d ", opt[pos][i] + 1), pos = opt[pos][i];
	return 0;
}

Compilation message

sequence.cpp: In function 'int main()':
sequence.cpp:50:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |  scanf("%d%d", &n, &k);
      |  ~~~~~^~~~~~~~~~~~~~~~
sequence.cpp:51:32: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |  for(int i = 0;i < n;i++) scanf("%d", A + i);
      |                           ~~~~~^~~~~~~~~~~~~

Subtask #1
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB contestant found the optimal answer: 108 == 108
2 Correct 1 ms 212 KB contestant found the optimal answer: 999 == 999
3 Correct 1 ms 212 KB contestant found the optimal answer: 0 == 0
4 Correct 1 ms 340 KB contestant found the optimal answer: 1542524 == 1542524
5 Incorrect 1 ms 340 KB declared answer doesn't correspond to the split scheme: declared = -2147483648, real = 4500000000
6 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 340 KB contestant didn't find the optimal answer: 984279 < 1093956
2 Halted 0 ms 0 KB -

Subtask #3
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 436 KB contestant didn't find the optimal answer: 6318034 < 610590000
2 Halted 0 ms 0 KB -

Subtask #4
0 / 17.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 1204 KB contestant didn't find the optimal answer: 21219127 < 21503404
2 Halted 0 ms 0 KB -

Subtask #5
0 / 21.0

# Verdict Execution time Memory Grader output
1 Incorrect 7 ms 9048 KB contestant didn't find the optimal answer: 1059360832 < 1818678304
2 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Incorrect 67 ms 86688 KB declared answer doesn't correspond to the split scheme: declared = -2147483648, real = 8503126575
2 Halted 0 ms 0 KB -